From 7933312374915f54f3dd8577d095fe340c30e9c6 Mon Sep 17 00:00:00 2001
From: Andy Norwood <andytnorwood@gmail.com>
Date: Thu, 12 Mar 2026 10:23:02 +0000
Subject: [PATCH 01/22] fix: use get_librenms_sync_device() in verify views to
 prevent VC crash

Replace inline VC resolution logic in SingleCableVerifyView and
SingleInterfaceVerifyView with the centralized get_librenms_sync_device()
utility. The inline logic only checked primary_ip, causing a 500 error
(AttributeError: 'NoneType' object has no attribute '_meta') when no VC
member has a primary_ip set.

get_librenms_sync_device() handles this by also checking librenms_id and
falling back to lowest vc_position. Added None guards for the edge case
where no sync device can be resolved at all.

Includes 8 new tests covering both views' VC resolution paths.
---
 .../tests/test_verify_views.py                | 204 ++++++++++++++++++
 .../views/base/cables_view.py                 |  13 +-
 .../views/object_sync/devices.py              |  12 +-
 3 files changed, 216 insertions(+), 13 deletions(-)
 create mode 100644 netbox_librenms_plugin/tests/test_verify_views.py

diff --git a/netbox_librenms_plugin/tests/test_verify_views.py b/netbox_librenms_plugin/tests/test_verify_views.py
new file mode 100644
index 0000000000..865a25e246
--- /dev/null
+++ b/netbox_librenms_plugin/tests/test_verify_views.py
@@ -0,0 +1,204 @@
+"""Tests for SingleCableVerifyView and SingleInterfaceVerifyView VC resolution.
+
+Covers the fix for the NoneType crash when a VC device has no primary_ip
+on any member — both views must use get_librenms_sync_device() and guard
+against None.
+"""
+
+import json
+from unittest.mock import MagicMock, patch
+
+
+def _make_request(body: dict) -> MagicMock:
+    """Create a mock POST request with JSON body."""
+    request = MagicMock()
+    request.body = json.dumps(body).encode()
+    request.user.has_perm.return_value = True
+    return request
+
+
+def _make_device(pk=1, has_vc=False, name="test-device"):
+    """Create a mock Device with optional virtual_chassis."""
+    device = MagicMock()
+    device.pk = pk
+    device.id = pk
+    device.name = name
+    device._meta.model_name = "device"
+    device.virtual_chassis = MagicMock() if has_vc else None
+    device.interfaces.filter.return_value.first.return_value = None
+    return device
+
+
+# ---------------------------------------------------------------------------
+# SingleCableVerifyView
+# ---------------------------------------------------------------------------
+class TestSingleCableVerifyView:
+    """SingleCableVerifyView.post() VC resolution and None guard."""
+
+    def _make_view(self):
+        from netbox_librenms_plugin.views.base.cables_view import SingleCableVerifyView
+
+        view = object.__new__(SingleCableVerifyView)
+        view._librenms_api = MagicMock()
+        return view
+
+    @patch("netbox_librenms_plugin.views.base.cables_view.get_object_or_404")
+    @patch("netbox_librenms_plugin.views.base.cables_view.get_librenms_sync_device")
+    @patch("netbox_librenms_plugin.views.base.cables_view.cache")
+    def test_vc_device_no_primary_ip_returns_empty_row(self, mock_cache, mock_sync, mock_get_obj):
+        """VC with no primary_ip: get_librenms_sync_device returns None → empty row, no crash."""
+        device = _make_device(pk=1, has_vc=True)
+        mock_get_obj.return_value = device
+        mock_sync.return_value = None
+
+        view = self._make_view()
+        request = _make_request({"device_id": 1, "local_port_id": "42"})
+        response = view.post(request)
+
+        data = json.loads(response.content)
+        assert data["status"] == "success"
+        assert data["formatted_row"]["cable_status"] == "Missing Ports"
+        mock_cache.get.assert_not_called()
+
+    @patch("netbox_librenms_plugin.views.base.cables_view.get_object_or_404")
+    @patch("netbox_librenms_plugin.views.base.cables_view.get_librenms_sync_device")
+    @patch("netbox_librenms_plugin.views.base.cables_view.cache")
+    def test_vc_device_with_sync_device_uses_cache(self, mock_cache, mock_sync, mock_get_obj):
+        """VC with valid sync device: cache is queried with the sync device's key."""
+        device = _make_device(pk=1, has_vc=True)
+        sync_device = _make_device(pk=2, name="sync-device")
+        mock_get_obj.return_value = device
+        mock_sync.return_value = sync_device
+        mock_cache.get.return_value = None  # No cached data
+
+        view = self._make_view()
+        request = _make_request({"device_id": 1, "local_port_id": "42"})
+        view.post(request)
+
+        mock_sync.assert_called_once_with(device)
+        mock_cache.get.assert_called_once()
+        cache_key = mock_cache.get.call_args[0][0]
+        assert "device" in cache_key
+        assert "2" in cache_key
+
+    @patch("netbox_librenms_plugin.views.base.cables_view.get_object_or_404")
+    @patch("netbox_librenms_plugin.views.base.cables_view.get_librenms_sync_device")
+    @patch("netbox_librenms_plugin.views.base.cables_view.cache")
+    def test_non_vc_device_skips_sync_device_lookup(self, mock_cache, mock_sync, mock_get_obj):
+        """Non-VC device: get_librenms_sync_device is NOT called."""
+        device = _make_device(pk=5, has_vc=False)
+        mock_get_obj.return_value = device
+        mock_cache.get.return_value = None
+
+        view = self._make_view()
+        request = _make_request({"device_id": 5, "local_port_id": "10"})
+        view.post(request)
+
+        mock_sync.assert_not_called()
+        mock_cache.get.assert_called_once()
+
+    def test_no_device_id_returns_empty_row(self):
+        """Missing device_id: returns default empty formatted_row."""
+        view = self._make_view()
+        request = _make_request({"local_port_id": "42"})
+        response = view.post(request)
+
+        data = json.loads(response.content)
+        assert data["status"] == "success"
+        assert data["formatted_row"]["cable_status"] == "Missing Ports"
+
+
+# ---------------------------------------------------------------------------
+# SingleInterfaceVerifyView
+# ---------------------------------------------------------------------------
+class TestSingleInterfaceVerifyView:
+    """SingleInterfaceVerifyView.post() VC resolution and None guard."""
+
+    def _make_view(self):
+        from netbox_librenms_plugin.views.object_sync.devices import SingleInterfaceVerifyView
+
+        view = object.__new__(SingleInterfaceVerifyView)
+        return view
+
+    @patch("netbox_librenms_plugin.views.object_sync.devices.get_object_or_404")
+    @patch("netbox_librenms_plugin.views.object_sync.devices.get_librenms_sync_device")
+    @patch("netbox_librenms_plugin.views.object_sync.devices.cache")
+    def test_vc_device_no_sync_device_returns_404(self, mock_cache, mock_sync, mock_get_obj):
+        """VC with no sync device: returns 404 JSON error, no crash."""
+        device = _make_device(pk=1, has_vc=True)
+        mock_get_obj.return_value = device
+        mock_sync.return_value = None
+
+        view = self._make_view()
+        request = _make_request(
+            {
+                "device_id": 1,
+                "interface_name": "eth0",
+                "interface_name_field": "ifName",
+            }
+        )
+        response = view.post(request)
+
+        assert response.status_code == 404
+        data = json.loads(response.content)
+        assert data["status"] == "error"
+        assert "sync device" in data["message"].lower()
+        mock_cache.get.assert_not_called()
+
+    @patch("netbox_librenms_plugin.views.object_sync.devices.get_object_or_404")
+    @patch("netbox_librenms_plugin.views.object_sync.devices.get_librenms_sync_device")
+    @patch("netbox_librenms_plugin.views.object_sync.devices.cache")
+    def test_vc_device_with_sync_device_uses_cache(self, mock_cache, mock_sync, mock_get_obj):
+        """VC with valid sync device: cache is queried with the sync device's key."""
+        device = _make_device(pk=1, has_vc=True)
+        sync_device = _make_device(pk=3, name="sync-member")
+        mock_get_obj.return_value = device
+        mock_sync.return_value = sync_device
+        mock_cache.get.return_value = None
+
+        view = self._make_view()
+        request = _make_request(
+            {
+                "device_id": 1,
+                "interface_name": "eth0",
+                "interface_name_field": "ifName",
+            }
+        )
+        view.post(request)
+
+        mock_sync.assert_called_once_with(device)
+        mock_cache.get.assert_called_once()
+        cache_key = mock_cache.get.call_args[0][0]
+        assert "3" in cache_key
+
+    @patch("netbox_librenms_plugin.views.object_sync.devices.get_object_or_404")
+    @patch("netbox_librenms_plugin.views.object_sync.devices.get_librenms_sync_device")
+    @patch("netbox_librenms_plugin.views.object_sync.devices.cache")
+    def test_non_vc_device_skips_sync_device_lookup(self, mock_cache, mock_sync, mock_get_obj):
+        """Non-VC device: get_librenms_sync_device is NOT called."""
+        device = _make_device(pk=5, has_vc=False)
+        mock_get_obj.return_value = device
+        mock_cache.get.return_value = None
+
+        view = self._make_view()
+        request = _make_request(
+            {
+                "device_id": 5,
+                "interface_name": "eth0",
+                "interface_name_field": "ifName",
+            }
+        )
+        view.post(request)
+
+        mock_sync.assert_not_called()
+        mock_cache.get.assert_called_once()
+
+    def test_no_device_id_returns_400(self):
+        """Missing device_id: returns 400 error."""
+        view = self._make_view()
+        request = _make_request({"interface_name": "eth0"})
+        response = view.post(request)
+
+        assert response.status_code == 400
+        data = json.loads(response.content)
+        assert data["status"] == "error"
diff --git a/netbox_librenms_plugin/views/base/cables_view.py b/netbox_librenms_plugin/views/base/cables_view.py
index cff041c64e..f09a62561e 100644
--- a/netbox_librenms_plugin/views/base/cables_view.py
+++ b/netbox_librenms_plugin/views/base/cables_view.py
@@ -14,6 +14,7 @@
 
 from netbox_librenms_plugin.utils import (
     get_interface_name_field,
+    get_librenms_sync_device,
     get_virtual_chassis_member,
 )
 from netbox_librenms_plugin.views.mixins import CacheMixin, LibreNMSAPIMixin, LibreNMSPermissionMixin
@@ -363,17 +364,15 @@ def post(self, request):
         if selected_device_id:
             selected_device = get_object_or_404(Device, pk=selected_device_id)
 
-            # Get the primary device (master or first with IP) if part of virtual chassis
+            # Resolve the VC device that holds cached LibreNMS data
             if selected_device.virtual_chassis:
-                primary_device = selected_device.virtual_chassis.master
-                if not primary_device or not primary_device.primary_ip:
-                    primary_device = next(
-                        (member for member in selected_device.virtual_chassis.members.all() if member.primary_ip),
-                        None,
-                    )
+                primary_device = get_librenms_sync_device(selected_device)
             else:
                 primary_device = selected_device
 
+            if not primary_device:
+                return JsonResponse({"status": "success", "formatted_row": formatted_row})
+
             cached_links = cache.get(self.get_cache_key(primary_device, "links"))
 
             if cached_links:
diff --git a/netbox_librenms_plugin/views/object_sync/devices.py b/netbox_librenms_plugin/views/object_sync/devices.py
index 97584f8319..5859cc4a67 100644
--- a/netbox_librenms_plugin/views/object_sync/devices.py
+++ b/netbox_librenms_plugin/views/object_sync/devices.py
@@ -19,6 +19,7 @@
 )
 from netbox_librenms_plugin.utils import (
     get_interface_name_field,
+    get_librenms_sync_device,
     get_missing_vlan_warning,
     get_tagged_vlan_css_class,
     get_untagged_vlan_css_class,
@@ -106,16 +107,15 @@ def post(self, request):
 
         selected_device = get_object_or_404(Device, pk=selected_device_id)
 
+        # Resolve the VC device that holds cached LibreNMS data
         if selected_device.virtual_chassis:
-            primary_device = selected_device.virtual_chassis.master
-            if not primary_device or not primary_device.primary_ip:
-                primary_device = next(
-                    (member for member in selected_device.virtual_chassis.members.all() if member.primary_ip),
-                    None,
-                )
+            primary_device = get_librenms_sync_device(selected_device)
         else:
             primary_device = selected_device
 
+        if not primary_device:
+            return JsonResponse({"status": "error", "message": "No sync device found for virtual chassis"}, status=404)
+
         cached_data = cache.get(self.get_cache_key(primary_device, "ports"))
 
         if cached_data:

From f5b9dedf9d8cbef58bc6f5f763d5868298aa0d84 Mon Sep 17 00:00:00 2001
From: Andy Norwood <andytnorwood@gmail.com>
Date: Thu, 12 Mar 2026 13:17:46 +0000
Subject: [PATCH 02/22] =?UTF-8?q?refactor:=20address=20PR=20review=20?=
 =?UTF-8?q?=E2=80=94=20fix=20test=20docstrings,=20use=20conftest=20fixture?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

- Rename tests to reflect actual None scenario (no resolvable sync device,
  not 'no primary_ip') per reviewer feedback on comments 1 & 2
- Replace _make_device() with _make_vc_device() for VC-only cases; use
  mock_netbox_device conftest fixture for non-VC test cases per comment 4
---
 .../tests/test_verify_views.py                | 52 +++++++++----------
 1 file changed, 26 insertions(+), 26 deletions(-)

diff --git a/netbox_librenms_plugin/tests/test_verify_views.py b/netbox_librenms_plugin/tests/test_verify_views.py
index 865a25e246..4007f04f76 100644
--- a/netbox_librenms_plugin/tests/test_verify_views.py
+++ b/netbox_librenms_plugin/tests/test_verify_views.py
@@ -1,8 +1,8 @@
 """Tests for SingleCableVerifyView and SingleInterfaceVerifyView VC resolution.
 
-Covers the fix for the NoneType crash when a VC device has no primary_ip
-on any member — both views must use get_librenms_sync_device() and guard
-against None.
+Verifies that both views delegate VC device resolution to
+get_librenms_sync_device() and handle the None return gracefully
+(e.g. empty VC members or vc_position type errors).
 """
 
 import json
@@ -17,14 +17,14 @@ def _make_request(body: dict) -> MagicMock:
     return request
 
 
-def _make_device(pk=1, has_vc=False, name="test-device"):
-    """Create a mock Device with optional virtual_chassis."""
+def _make_vc_device(pk=1, name="vc-device"):
+    """Create a mock Device that belongs to a virtual chassis."""
     device = MagicMock()
     device.pk = pk
     device.id = pk
     device.name = name
     device._meta.model_name = "device"
-    device.virtual_chassis = MagicMock() if has_vc else None
+    device.virtual_chassis = MagicMock()
     device.interfaces.filter.return_value.first.return_value = None
     return device
 
@@ -45,9 +45,9 @@ def _make_view(self):
     @patch("netbox_librenms_plugin.views.base.cables_view.get_object_or_404")
     @patch("netbox_librenms_plugin.views.base.cables_view.get_librenms_sync_device")
     @patch("netbox_librenms_plugin.views.base.cables_view.cache")
-    def test_vc_device_no_primary_ip_returns_empty_row(self, mock_cache, mock_sync, mock_get_obj):
-        """VC with no primary_ip: get_librenms_sync_device returns None → empty row, no crash."""
-        device = _make_device(pk=1, has_vc=True)
+    def test_vc_no_resolvable_sync_device_returns_empty_row(self, mock_cache, mock_sync, mock_get_obj):
+        """VC where get_librenms_sync_device returns None → empty row, no crash."""
+        device = _make_vc_device(pk=1)
         mock_get_obj.return_value = device
         mock_sync.return_value = None
 
@@ -63,10 +63,10 @@ def test_vc_device_no_primary_ip_returns_empty_row(self, mock_cache, mock_sync,
     @patch("netbox_librenms_plugin.views.base.cables_view.get_object_or_404")
     @patch("netbox_librenms_plugin.views.base.cables_view.get_librenms_sync_device")
     @patch("netbox_librenms_plugin.views.base.cables_view.cache")
-    def test_vc_device_with_sync_device_uses_cache(self, mock_cache, mock_sync, mock_get_obj):
-        """VC with valid sync device: cache is queried with the sync device's key."""
-        device = _make_device(pk=1, has_vc=True)
-        sync_device = _make_device(pk=2, name="sync-device")
+    def test_vc_resolved_sync_device_uses_cache(self, mock_cache, mock_sync, mock_get_obj):
+        """VC with resolved sync device: cache is queried with that device's key."""
+        device = _make_vc_device(pk=1)
+        sync_device = _make_vc_device(pk=2, name="sync-device")
         mock_get_obj.return_value = device
         mock_sync.return_value = sync_device
         mock_cache.get.return_value = None  # No cached data
@@ -84,10 +84,10 @@ def test_vc_device_with_sync_device_uses_cache(self, mock_cache, mock_sync, mock
     @patch("netbox_librenms_plugin.views.base.cables_view.get_object_or_404")
     @patch("netbox_librenms_plugin.views.base.cables_view.get_librenms_sync_device")
     @patch("netbox_librenms_plugin.views.base.cables_view.cache")
-    def test_non_vc_device_skips_sync_device_lookup(self, mock_cache, mock_sync, mock_get_obj):
+    def test_non_vc_device_skips_sync_device_lookup(self, mock_cache, mock_sync, mock_get_obj, mock_netbox_device):
         """Non-VC device: get_librenms_sync_device is NOT called."""
-        device = _make_device(pk=5, has_vc=False)
-        mock_get_obj.return_value = device
+        mock_netbox_device.virtual_chassis = None
+        mock_get_obj.return_value = mock_netbox_device
         mock_cache.get.return_value = None
 
         view = self._make_view()
@@ -123,9 +123,9 @@ def _make_view(self):
     @patch("netbox_librenms_plugin.views.object_sync.devices.get_object_or_404")
     @patch("netbox_librenms_plugin.views.object_sync.devices.get_librenms_sync_device")
     @patch("netbox_librenms_plugin.views.object_sync.devices.cache")
-    def test_vc_device_no_sync_device_returns_404(self, mock_cache, mock_sync, mock_get_obj):
-        """VC with no sync device: returns 404 JSON error, no crash."""
-        device = _make_device(pk=1, has_vc=True)
+    def test_vc_no_resolvable_sync_device_returns_404(self, mock_cache, mock_sync, mock_get_obj):
+        """VC where get_librenms_sync_device returns None → 404 JSON error, no crash."""
+        device = _make_vc_device(pk=1)
         mock_get_obj.return_value = device
         mock_sync.return_value = None
 
@@ -148,10 +148,10 @@ def test_vc_device_no_sync_device_returns_404(self, mock_cache, mock_sync, mock_
     @patch("netbox_librenms_plugin.views.object_sync.devices.get_object_or_404")
     @patch("netbox_librenms_plugin.views.object_sync.devices.get_librenms_sync_device")
     @patch("netbox_librenms_plugin.views.object_sync.devices.cache")
-    def test_vc_device_with_sync_device_uses_cache(self, mock_cache, mock_sync, mock_get_obj):
-        """VC with valid sync device: cache is queried with the sync device's key."""
-        device = _make_device(pk=1, has_vc=True)
-        sync_device = _make_device(pk=3, name="sync-member")
+    def test_vc_resolved_sync_device_uses_cache(self, mock_cache, mock_sync, mock_get_obj):
+        """VC with resolved sync device: cache is queried with that device's key."""
+        device = _make_vc_device(pk=1)
+        sync_device = _make_vc_device(pk=3, name="sync-member")
         mock_get_obj.return_value = device
         mock_sync.return_value = sync_device
         mock_cache.get.return_value = None
@@ -174,10 +174,10 @@ def test_vc_device_with_sync_device_uses_cache(self, mock_cache, mock_sync, mock
     @patch("netbox_librenms_plugin.views.object_sync.devices.get_object_or_404")
     @patch("netbox_librenms_plugin.views.object_sync.devices.get_librenms_sync_device")
     @patch("netbox_librenms_plugin.views.object_sync.devices.cache")
-    def test_non_vc_device_skips_sync_device_lookup(self, mock_cache, mock_sync, mock_get_obj):
+    def test_non_vc_device_skips_sync_device_lookup(self, mock_cache, mock_sync, mock_get_obj, mock_netbox_device):
         """Non-VC device: get_librenms_sync_device is NOT called."""
-        device = _make_device(pk=5, has_vc=False)
-        mock_get_obj.return_value = device
+        mock_netbox_device.virtual_chassis = None
+        mock_get_obj.return_value = mock_netbox_device
         mock_cache.get.return_value = None
 
         view = self._make_view()

From 232f37d9fbdfc8cba665258a6bffb49930c8d26c Mon Sep 17 00:00:00 2001
From: Marcin Zieba <marcinpsk@gmail.com>
Date: Thu, 12 Mar 2026 08:18:36 +0000
Subject: [PATCH 03/22] feat(multi-server): JSON custom field librenms_id with
 server management and CR fixes
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

- Multi-server librenms_id as JSON custom field (server_key → device_id map)
- Server management UI, migration of legacy integer IDs
- CR fixes: int conversion guard, VLAN dict guard, VC domain with server_key,
  forms has_option_only, JS server_key selector, _cancelled flag in bulk import,
  cache sort_keys, role recalculate, XSS escape, bool guards
- Update existing tests for multi-server behavior
- test_librenms_id.py: tests for new JSON CF format and migration
---
 .devcontainer/README.md                       |   23 +-
 .github/pull_request_template.md              |    2 +-
 .pre-commit-config.yaml                       |    6 +-
 docs/development/testing.md                   |   23 +-
 docs/usage_tips/custom_field.md               |   10 +-
 netbox_librenms_plugin/forms.py               |   60 +-
 .../import_utils/__init__.py                  |    1 +
 .../import_utils/bulk_import.py               |  321 +-
 netbox_librenms_plugin/import_utils/cache.py  |   84 +-
 .../import_utils/device_operations.py         |  114 +-
 .../import_utils/filters.py                   |   57 +-
 .../import_utils/virtual_chassis.py           |  198 +-
 .../import_utils/vm_operations.py             |   96 +-
 netbox_librenms_plugin/jobs.py                |   31 +-
 netbox_librenms_plugin/librenms_api.py        |  169 +-
 .../js/librenms_sync.js                       |  295 +-
 .../tables/device_status.py                   |    6 +-
 netbox_librenms_plugin/tables/interfaces.py   |   10 +-
 netbox_librenms_plugin/tables/ipaddresses.py  |    6 +-
 netbox_librenms_plugin/tables/vlans.py        |   40 +-
 .../_cable_sync_content.html                  |    1 +
 .../_interface_sync_content.html              |    1 +
 .../_ipaddress_sync_content.html              |    1 +
 .../_vlan_sync_content.html                   |    1 +
 .../htmx/device_validation_details.html       |   59 +-
 .../librenms_sync_base.html                   |   95 +-
 netbox_librenms_plugin/tests/conftest.py      |   53 +-
 .../tests/mock_librenms_server.py             |   40 +
 .../tests/test_background_jobs.py             |   15 +-
 .../tests/test_import_utils.py                | 3721 +++++++++++++++--
 .../tests/test_integration_sync.py            |   48 +
 .../tests/test_librenms_api.py                |  123 +-
 .../tests/test_librenms_id.py                 |  505 +++
 netbox_librenms_plugin/tests/test_mixins.py   |   53 +
 .../tests/test_permissions.py                 |  134 +-
 .../tests/test_sync_devices.py                |  107 +
 .../tests/test_sync_view_mismatch.py          |  259 +-
 netbox_librenms_plugin/tests/test_utils.py    |  197 +-
 .../tests/test_view_wiring.py                 |  174 +-
 .../tests/test_vlan_sync.py                   |   22 +
 netbox_librenms_plugin/urls.py                |   12 +
 netbox_librenms_plugin/utils.py               |  273 +-
 netbox_librenms_plugin/views/__init__.py      |    2 +
 .../views/base/cables_view.py                 |  148 +-
 .../views/base/interfaces_view.py             |   27 +-
 .../views/base/ip_addresses_view.py           |   54 +-
 .../views/base/librenms_sync_view.py          |  128 +-
 .../views/base/vlan_table_view.py             |   16 +-
 .../views/imports/actions.py                  |  418 +-
 netbox_librenms_plugin/views/imports/list.py  |    8 +-
 netbox_librenms_plugin/views/mixins.py        |   37 +-
 .../views/object_sync/devices.py              |   46 +-
 .../views/object_sync/vms.py                  |   16 +-
 netbox_librenms_plugin/views/sync/cables.py   |   58 +-
 .../views/sync/device_fields.py               |  239 +-
 netbox_librenms_plugin/views/sync/devices.py  |   15 +-
 .../views/sync/interfaces.py                  |   40 +-
 .../views/sync/ip_addresses.py                |   21 +-
 netbox_librenms_plugin/views/sync/vlans.py    |   20 +-
 pyproject.toml                                |    6 +
 uv.lock                                       |    8 +
 61 files changed, 7564 insertions(+), 1189 deletions(-)
 create mode 100644 netbox_librenms_plugin/tests/test_librenms_id.py
 create mode 100644 uv.lock

diff --git a/.devcontainer/README.md b/.devcontainer/README.md
index 3560a93af3..7dc3ef967a 100644
--- a/.devcontainer/README.md
+++ b/.devcontainer/README.md
@@ -44,20 +44,20 @@ If you need to test with a LibreNMS instance on a private network (local lab, co
 
 1. Fork and Clone: fork the plugin repo in Github and clone locally
 2. Open in VS Code and choose "Reopen in Container" (or Ctrl+Shift+P → Dev Containers: Reopen in Container)
-2. Wait for setup (~5min on first run or when new NetBox image is used). The container will install the plugin and prep NetBox
-3. Set up GitHub access: `gh auth login` (for pushing/pulling code changes)
-4. Create your plugin config — see [Plugin configuration](#plugin-configuration):
+3. Wait for setup (~5min on first run or when new NetBox image is used). The container will install the plugin and prep NetBox
+4. Set up GitHub access: `gh auth login` (for pushing/pulling code changes)
+5. Create your plugin config — see [LibreNMS Server configuration](#librenms-server-configuration):
    - `cp .devcontainer/config/plugin-config.py.example .devcontainer/config/plugin-config.py`
    - Edit it with your server details (tokens/URLs)
-5. Start NetBox with `netbox-run` (or `netbox-run-bg` in background) (see [Commands](#-commands-aliases))
-6. Access NetBox at http://localhost:8000
+6. Start NetBox with `netbox-run` (or `netbox-run-bg` in background) (see [Commands](#-commands-aliases))
+7. Access NetBox at http://localhost:8000
    - Username: `admin`
    - Password: `admin`
 
 ### 🔄 Code changes and Committing
 8. Edit code in the repo root.  Check out [contributing docs](../docs/contributing.md)
 9. Use `netbox-logs` to follow log output on screen
-6. Commit changes and contribute as normal by submitting a PR on GitHub.
+10. Commit changes and contribute as normal by submitting a PR on GitHub.
 
 ### Quick Tips
 - **Auto-reload**: Works for most code changes when `DEBUG=True`
@@ -241,7 +241,7 @@ After any `.env` change, rebuild the dev container to apply environment updates.
 
 ### Additional packages (including other netbox plugins)
 - Create `.devcontainer/extra-requirements.txt` for extra Python packages. Example: `.devcontainer/extra-requirements.txt.example`.
-   - After changes: run `plugins-install` to install packages, then `netbox-restart` (see [Commands](#-commands-aliases))
+   - After changes: run `plugin-install` to install packages, then `netbox-restart` (see [Commands](#-commands-aliases))
 
 ## 🔧 Git Setup
 
@@ -259,7 +259,7 @@ The dev container includes Git and GitHub CLI pre-installed. You'll need to conf
 git remote -v
 
 # If it shows git@github.com:..., convert to HTTPS
-git remote set-url origin https://github.com/bonzo81/netbox-librenms-plugin.git
+git remote set-url origin https://github.com/<owner>/netbox-librenms-plugin.git
 ```
 
 ### Recommended: GitHub CLI (Easiest)
@@ -347,13 +347,14 @@ fatal: Could not read from remote repository.
 1. **Check remote URL** - should use HTTPS, not SSH:
    ```bash
    git remote -v
-   # Should show: https://github.com/bonzo81/netbox-librenms-plugin.git
-   # NOT: git@github.com:bonzo81/netbox-librenms-plugin.git
+   # Should show: https://github.com/<owner>/netbox-librenms-plugin.git
+   # NOT: git@github.com:<owner>/netbox-librenms-plugin.git
    ```
 
 2. **Fix SSH remote URL**:
+
    ```bash
-   git remote set-url origin https://github.com/bonzo81/netbox-librenms-plugin.git
+   git remote set-url origin https://github.com/<owner>/netbox-librenms-plugin.git
    ```
 
 3. **Authenticate with GitHub CLI**:
diff --git a/.github/pull_request_template.md b/.github/pull_request_template.md
index b641e68a71..99ff02374f 100644
--- a/.github/pull_request_template.md
+++ b/.github/pull_request_template.md
@@ -36,7 +36,7 @@ Delete items that don’t apply and describe briefly.
 3.
 
 ## Risk Assessment
-- Does this change affect existing users?  
+- Does this change affect existing users?
 - Could this cause unintended imports / updates?
 
 Explain briefly.
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 6669696bbb..7346e658ed 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -1,6 +1,6 @@
 repos:
   - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.15.4  # Use the latest version from https://github.com/astral-sh/ruff-pre-commit/releases
+    rev: v0.15.5  # Use the latest version from https://github.com/astral-sh/ruff-pre-commit/releases
     hooks:
       # Run the linter
       - id: ruff-check
@@ -15,5 +15,9 @@ repos:
       - id: end-of-file-fixer
       - id: check-yaml
         exclude: ^mkdocs\.yml$
+      - id: check-yaml
+        name: check-yaml (mkdocs.yml --unsafe)
+        args: [--unsafe]
+        files: ^mkdocs\.yml$
       - id: check-added-large-files
       - id: check-merge-conflict
diff --git a/docs/development/testing.md b/docs/development/testing.md
index 05d27bd4ed..58f041c09e 100644
--- a/docs/development/testing.md
+++ b/docs/development/testing.md
@@ -35,8 +35,18 @@ The test suite covers all major plugin functionality. Tests are organized by the
 | [test_sync_interfaces.py](../../netbox_librenms_plugin/tests/test_sync_interfaces.py) | Interface sync—port matching, attribute updates, MAC handling, librenms_id assignment |
 | [test_virtual_chassis.py](../../netbox_librenms_plugin/tests/test_virtual_chassis.py) | Virtual chassis detection—VC member naming patterns and name generation |
 | [test_sync_view_mismatch.py](../../netbox_librenms_plugin/tests/test_sync_view_mismatch.py) | Sync page context—device type mismatch detection and badge rendering |
+| [test_coverage_device_fields.py](../../netbox_librenms_plugin/tests/test_coverage_device_fields.py) | Device field sync view—field update logic and device field mapping |
+| [test_coverage_list.py](../../netbox_librenms_plugin/tests/test_coverage_list.py) | Import list view—background job decision, job result loading, and GET handler |
+| [test_coverage_api.py](../../netbox_librenms_plugin/tests/test_coverage_api.py) | LibreNMS API client—malformed payload guards, error paths, and edge cases |
+| [test_coverage_sync_view.py](../../netbox_librenms_plugin/tests/test_coverage_sync_view.py) | Sync view base class—context preparation and tab rendering |
+| [test_coverage_filters.py](../../netbox_librenms_plugin/tests/test_coverage_filters.py) | Import filter logic—filter form processing and device count helpers |
+| [test_sync_modules.py](../../netbox_librenms_plugin/tests/test_sync_modules.py) | Module sync—inventory matching, module type resolution, and normalization rules |
+| [test_modules_view.py](../../netbox_librenms_plugin/tests/test_modules_view.py) | Module sync view—context preparation, table rendering, and module bay mapping |
+| [test_tables_modules.py](../../netbox_librenms_plugin/tests/test_tables_modules.py) | Module tables—column rendering, row formatting, and action buttons |
 | [test_permissions.py](../../netbox_librenms_plugin/tests/test_permissions.py) | Permission enforcement—mixin contracts, object-level permissions, and write guards |
+| [test_vm_operations.py](../../netbox_librenms_plugin/tests/test_vm_operations.py) | VM operations—virtual machine sync, interface handling, and VM-specific views |
 | [test_integration_sync.py](../../netbox_librenms_plugin/tests/test_integration_sync.py) | Integration tests—API client against local mock HTTP server |
+| [test_integration_virtual_chassis.py](../../netbox_librenms_plugin/tests/test_integration_virtual_chassis.py) | Integration tests—VC detection, negative cache, multi-server cache isolation |
 | [test_view_wiring.py](../../netbox_librenms_plugin/tests/test_view_wiring.py) | Smoke tests—view class MRO, mixin wiring, permission contracts, and template syntax |
 
 Supporting files:
@@ -77,15 +87,15 @@ pytest netbox_librenms_plugin/tests/test_background_jobs.py -v
 # Multi-server librenms_id tests
 pytest netbox_librenms_plugin/tests/test_librenms_id.py -v
 
-# Sync view tests (devices, interfaces)
-pytest netbox_librenms_plugin/tests/test_sync_devices.py netbox_librenms_plugin/tests/test_sync_interfaces.py -v
-
-# Sync view mismatch detection and permission enforcement
-pytest netbox_librenms_plugin/tests/test_sync_view_mismatch.py netbox_librenms_plugin/tests/test_permissions.py -v
+# Sync view tests (devices, interfaces, modules)
+pytest netbox_librenms_plugin/tests/test_sync_devices.py netbox_librenms_plugin/tests/test_sync_interfaces.py netbox_librenms_plugin/tests/test_sync_modules.py -v
 
 # Integration tests (API client against mock HTTP server)
 pytest netbox_librenms_plugin/tests/test_integration_sync.py -v
 
+# Sync view mismatch detection and permission enforcement
+pytest netbox_librenms_plugin/tests/test_sync_view_mismatch.py netbox_librenms_plugin/tests/test_permissions.py -v
+
 # View wiring and template syntax smoke tests
 pytest netbox_librenms_plugin/tests/test_view_wiring.py -v
 ```
@@ -111,9 +121,10 @@ pytest netbox_librenms_plugin/tests/ -v --lf
 The test suite prioritizes speed and isolation so you can run tests frequently during development:
 
 - **Mock-based**: Unit tests use `MagicMock` instead of real database objects. No Django database setup required.
-- **Fast execution**: The full suite runs in under 0.5 seconds.
+- **Fast execution**: The full suite runs in approximately 15-20 seconds (varies by environment).
 - **Isolated**: Each test is independent with no shared state between tests.
 - **No external network access**: Tests never call external services. Integration tests use a local loopback HTTP server (`mock_librenms_server.py`) to exercise the real API client against realistic HTTP responses without requiring a running LibreNMS instance.
+- **Coverage exclusions**: Test files themselves are excluded from coverage reports (see `[tool.coverage.run]` omit list in `pyproject.toml`).
 
 This approach means tests work identically in your local development environment, in the devcontainer, and in CI pipelines.
 
diff --git a/docs/usage_tips/custom_field.md b/docs/usage_tips/custom_field.md
index 032812ed82..0127d19efc 100644
--- a/docs/usage_tips/custom_field.md
+++ b/docs/usage_tips/custom_field.md
@@ -38,7 +38,15 @@ Follow these steps to create the `librenms_id` custom field in NetBox:
     - **Name:** `librenms_id`
     - **Label:** `LibreNMS ID`
     - **Description:** (Optional) Add a description like "LibreNMS Device ID for synchronization".
-    - **Type:** Integer
+    - **Type:** JSON (object) — stores a per-server mapping.
+      - Multi-server example:
+        ```json
+        {"production": 42, "staging": 17}
+        ```
+      - Legacy single-server example (integer):
+        ```
+        42
+        ```
     - **Required:** Leave unchecked (optional).
     - **Default Value:** Leave blank.
 
diff --git a/netbox_librenms_plugin/forms.py b/netbox_librenms_plugin/forms.py
index f3e3d075e5..42c693a7bd 100644
--- a/netbox_librenms_plugin/forms.py
+++ b/netbox_librenms_plugin/forms.py
@@ -4,6 +4,7 @@
 from dcim.choices import InterfaceTypeChoices
 from dcim.models import Device, DeviceRole, DeviceType, Location, Rack, Site
 from django import forms
+from django.db.models import Case, IntegerField, Value, When
 from django.http import QueryDict
 from django.utils.translation import gettext_lazy as _
 from netbox.forms import (
@@ -60,8 +61,8 @@ def _get_librenms_poller_group_choices():
         api = LibreNMSAPI()
         success, poller_groups = api.get_poller_groups()
 
-        if success and poller_groups:
-            for group in poller_groups:
+        if success:
+            for group in poller_groups or []:
                 group_id = str(group.get("id", ""))
                 group_name = group.get("group_name", "")
                 group_descr = group.get("descr", "")
@@ -545,8 +546,21 @@ def __init__(self, *args, **kwargs):
             ]
             has_filters = any(data.get(field) for field in filter_fields)
 
-            # Apply default only on initial load (no filters, no job_id)
-            if "use_background_job" not in data and not data.get("job_id") and not has_filters:
+            # Option-only fields that don't constitute a real search submission
+            option_only_fields = [
+                "show_disabled",
+                "enable_vc_detection",
+                "clear_cache",
+                "exclude_existing",
+                "apply_filters",
+            ]
+            non_option_fields = [
+                f for f in data if f not in option_only_fields + ["csrfmiddlewaretoken", "use_background_job"]
+            ]
+            has_option_only = bool(data) and not bool(non_option_fields) and not has_filters
+
+            # Apply default only on initial load (no filters, no job_id, no real submission)
+            if "use_background_job" not in data and not data.get("job_id") and not has_filters and not has_option_only:
                 data["use_background_job"] = "on"
             args = (data,) + args[1:]
 
@@ -577,19 +591,36 @@ def _populate_librenms_locations(self):
         """Fetch and populate LibreNMS locations in the dropdown."""
         from django.core.cache import cache
 
+        from netbox_librenms_plugin.import_utils.cache import get_location_choices_cache_key
         from netbox_librenms_plugin.librenms_api import LibreNMSAPI
 
         try:
-            # Use caching to avoid repeated API calls
-            cache_key = "librenms_locations_choices"
+            # Determine server_key cheaply from settings to check cache before instantiating the API
+            try:
+                from netbox_librenms_plugin.models import LibreNMSSettings
+
+                _settings = LibreNMSSettings.objects.first()
+                _server_key = (_settings.selected_server if _settings else None) or "default"
+            except Exception:
+                _server_key = "default"
+
+            cache_key = get_location_choices_cache_key(_server_key)
             cached_choices = cache.get(cache_key)
+            if cached_choices is not None:
+                self.fields["librenms_location"].choices = cached_choices
+                return
 
-            if cached_choices:
+            # Cache miss — instantiate the API client and fetch
+            api = LibreNMSAPI()
+            # Recompute cache_key with the resolved server_key in case it differs from settings
+            cache_key = get_location_choices_cache_key(api.server_key)
+            # Second cache check: the resolved server_key may differ from the settings key
+            cached_choices = cache.get(cache_key)
+            if cached_choices is not None:
                 self.fields["librenms_location"].choices = cached_choices
                 return
 
             # Fetch locations from LibreNMS
-            api = LibreNMSAPI()
             success, locations = api.get_locations()
 
             if success and locations:
@@ -752,8 +783,13 @@ def __init__(self, *args, **kwargs):
         if validation and validation.get("device_type", {}).get("suggestions"):
             suggestions = validation["device_type"]["suggestions"]
             if suggestions:
-                # Include suggested device types first, then all others
+                # Annotate with suggested_order so suggested types sort first
                 suggested_ids = [s["device_type"].id for s in suggestions]
-                self.fields["device_type"].queryset = DeviceType.objects.filter(
-                    id__in=suggested_ids
-                ) | DeviceType.objects.exclude(id__in=suggested_ids)
+                priority = Case(
+                    *[When(id=pk, then=Value(i)) for i, pk in enumerate(suggested_ids)],
+                    default=Value(len(suggested_ids)),
+                    output_field=IntegerField(),
+                )
+                self.fields["device_type"].queryset = DeviceType.objects.annotate(suggested_order=priority).order_by(
+                    "suggested_order", "manufacturer__name", "model"
+                )
diff --git a/netbox_librenms_plugin/import_utils/__init__.py b/netbox_librenms_plugin/import_utils/__init__.py
index b7a08fef59..81c24025ea 100644
--- a/netbox_librenms_plugin/import_utils/__init__.py
+++ b/netbox_librenms_plugin/import_utils/__init__.py
@@ -23,6 +23,7 @@
     get_active_cached_searches,
     get_cache_metadata_key,
     get_import_device_cache_key,
+    get_import_search_cache_key,
     get_validated_device_cache_key,
 )
 from .device_operations import (  # noqa: F401
diff --git a/netbox_librenms_plugin/import_utils/bulk_import.py b/netbox_librenms_plugin/import_utils/bulk_import.py
index f24b56bf44..aea305cb69 100644
--- a/netbox_librenms_plugin/import_utils/bulk_import.py
+++ b/netbox_librenms_plugin/import_utils/bulk_import.py
@@ -1,16 +1,19 @@
-"""Bulk import orchestration and filter processing."""
+"""Bulk import orchestration for devices and filter processing."""
 
+import hashlib
 import logging
 from typing import List
 
 from core.choices import JobStatusChoices
 from django.core.cache import cache
 
+from ..import_validation_helpers import apply_role_to_validation, recalculate_validation_status
 from ..librenms_api import LibreNMSAPI
+from ..utils import find_by_librenms_id
 from .cache import get_cache_metadata_key, get_import_device_cache_key, get_validated_device_cache_key
 from .device_operations import import_single_device, validate_device_for_import
 from .filters import get_librenms_devices_for_import
-from .permissions import require_permissions
+from .permissions import check_user_permissions, require_permissions
 from .virtual_chassis import (
     create_virtual_chassis_with_members,
     empty_virtual_chassis_data,
@@ -20,12 +23,36 @@
 logger = logging.getLogger(__name__)
 
 
+def _safe_disabled(device: dict) -> int:
+    """
+    Return 1 if the device is disabled, 0 otherwise.
+
+    Handles None, booleans, numeric strings, and common truthy/falsy tokens
+    (e.g. "true"/"yes"/"on" → 1, "false"/"no"/"off" → 0) without raising.
+    """
+    val = device.get("disabled", 0)
+    if isinstance(val, bool):
+        return int(val)
+    if isinstance(val, str):
+        normalized = val.strip().lower()
+        if normalized in ("1", "true", "yes", "on"):
+            return 1
+        if normalized in ("0", "false", "no", "off", ""):
+            return 0
+    try:
+        int_val = int(val)
+        return 1 if int_val else 0
+    except (TypeError, ValueError):
+        return 0
+
+
 def bulk_import_devices_shared(
     device_ids: List[int],
     server_key: str = None,
     sync_options: dict = None,
     manual_mappings_per_device: dict = None,
     libre_devices_cache: dict = None,
+    vc_detection_enabled: bool = False,
     job=None,
     user=None,
 ) -> dict:
@@ -43,6 +70,8 @@ def bulk_import_devices_shared(
             Example: {1179: {'device_role_id': 5}, 1180: {'device_role_id': 3}}
         libre_devices_cache: Optional dict mapping device_id to pre-fetched device data
             to avoid redundant API calls. Example: {123: {...device_data...}}
+        vc_detection_enabled: Whether to enable virtual chassis detection during import.
+            Should match the flag used during the filter/preview step for consistency.
         job: Optional JobRunner instance for progress logging and cancellation checks
         user: User performing the import (for permission checks). If job is provided,
             user is extracted from job.job.user if not explicitly passed.
@@ -70,11 +99,13 @@ def bulk_import_devices_shared(
     if user is None and job is not None:
         user = getattr(job.job, "user", None)
 
-    # Check permissions at start of bulk operation
+    # Check permissions at start of bulk operation — both device and VM perms are
+    # required because any device may be flagged as import_as_vm during validation.
     required_perms = [
         "dcim.add_device",
-        "dcim.add_interface",
-        "dcim.add_virtualchassis",
+        "dcim.change_device",
+        "virtualization.add_virtualmachine",
+        "virtualization.change_virtualmachine",
     ]
     require_permissions(user, required_perms, "import devices")
 
@@ -84,26 +115,42 @@ def bulk_import_devices_shared(
     skipped_list = []
     vc_created_count = 0
     processed_vc_domains = set()  # Track VCs already created by domain
+    _cancelled = False
 
     # Initialize API client once for all devices to avoid repeated config parsing
     api = LibreNMSAPI(server_key=server_key)
 
     for idx, device_id in enumerate(device_ids, start=1):
-        # Check for job cancellation every 5 devices
-        if job and idx % 5 == 0:
-            # Refresh job from DB to get current status
-            job.job.refresh_from_db()
-            job_status = job.job.status
-            status_value = job_status.value if hasattr(job_status, "value") else job_status
-            if status_value in (JobStatusChoices.STATUS_FAILED, "failed", "errored"):
-                if job.logger:
-                    job.logger.warning(f"Import job cancelled at device {idx} of {total}")
-                else:
-                    logger.warning(f"Import cancelled at device {idx} of {total}")
-                break
-            # Log progress
-            if job.logger:
-                job.logger.info(f"Imported device {idx} of {total}")
+        # Check for job cancellation on first iteration and every 5th thereafter.
+        # Check RQ/Redis state first (reflects stop API immediately); fall back to DB.
+        if job and (idx == 1 or idx % 5 == 0):
+            try:
+                from django_rq import get_queue
+                from rq.job import Job as RQJob
+
+                queue = get_queue("default")
+                rq_job = RQJob.fetch(str(job.job.job_id), connection=queue.connection)
+                if rq_job.is_failed or rq_job.is_stopped:
+                    if job.logger:
+                        job.logger.warning(
+                            f"Import job stopped at device {idx} of {total} (RQ status: {rq_job.get_status()})"
+                        )
+                    else:
+                        logger.warning(f"Import cancelled at device {idx} of {total}")
+                    _cancelled = True
+                    break
+            except Exception:
+                # Fall back to DB check if RQ is unavailable
+                job.job.refresh_from_db()
+                job_status = job.job.status
+                status_value = job_status.value if hasattr(job_status, "value") else job_status
+                if status_value in (JobStatusChoices.STATUS_FAILED, "failed", "errored"):
+                    if job.logger:
+                        job.logger.warning(f"Import job cancelled at device {idx} of {total}")
+                    else:
+                        logger.warning(f"Import cancelled at device {idx} of {total}")
+                    _cancelled = True
+                    break
 
         try:
             # Use cached device data if available to avoid redundant API calls
@@ -129,6 +176,8 @@ def bulk_import_devices_shared(
                 api=api,
                 use_sysname=use_sysname_opt,
                 strip_domain=strip_domain_opt,
+                server_key=api.server_key,
+                include_vc_detection=vc_detection_enabled,
             )
 
             # Build manual mappings from validation + any provided overrides
@@ -148,7 +197,8 @@ def bulk_import_devices_shared(
 
             result = import_single_device(
                 device_id,
-                server_key=server_key,
+                server_key=api.server_key,  # use resolved key, not raw parameter (may be None)
+                validation=validation,
                 sync_options=sync_options,
                 manual_mappings=device_mappings if device_mappings else None,
                 libre_device=libre_device,
@@ -162,6 +212,9 @@ def bulk_import_devices_shared(
                         "message": result["message"],
                     }
                 )
+                # Log progress after each successful import
+                if job and job.logger:
+                    job.logger.info(f"Imported device {idx} of {total}")
 
                 # Handle virtual chassis creation for stacks
                 vc_data = validation.get("virtual_chassis", {})
@@ -176,19 +229,45 @@ def bulk_import_devices_shared(
                         for m in vc_data.get("members", [])
                         if (serial := str(m.get("serial") or "").strip()) and serial != "-"
                     )
-                    vc_domain = (
-                        f"librenms-stack-{','.join(member_serials)}" if member_serials else f"librenms-{device_id}"
-                    )
-
+                    if member_serials:
+                        vc_domain = f"librenms-stack-{','.join(member_serials)}"
+                    else:
+                        # No serials available — build a stable fingerprint from member name/model/position
+                        # so all LibreNMS devices in the same physical stack share the same dedup key.
+                        member_parts = sorted(
+                            f"{m.get('name', '')}/{m.get('model', '')}:{m.get('position', 0)}"
+                            for m in vc_data.get("members", [])
+                        )
+                        if member_parts:
+                            fingerprint = hashlib.md5((f"{device_id}," + ",".join(member_parts)).encode()).hexdigest()[
+                                :12
+                            ]
+                            vc_domain = f"librenms-stack-{fingerprint}"
+                        else:
+                            vc_domain = f"librenms-{device_id}"
+
+                    # Guard VC creation with its own permission check — the upfront check
+                    # only covers add_device/change_device; VirtualChassis needs a separate perm.
+                    has_vc_perm, missing_vc_perms = check_user_permissions(user, ["dcim.add_virtualchassis"])
+                    if not has_vc_perm:
+                        warn_msg = (
+                            f"Skipping VC creation for device {device_id}: "
+                            f"missing permissions: {', '.join(missing_vc_perms)}"
+                        )
+                        if job and job.logger:
+                            job.logger.warning(warn_msg)
+                        else:
+                            logger.warning(warn_msg)
                     # Only create VC if we haven't processed this stack yet
                     # Add to set BEFORE attempting creation to prevent race condition
-                    if vc_domain not in processed_vc_domains:
+                    elif vc_domain not in processed_vc_domains:
                         processed_vc_domains.add(vc_domain)
                         try:
                             vc = create_virtual_chassis_with_members(
                                 result["device"],
                                 vc_data["members"],
                                 libre_device,
+                                server_key=api.server_key,
                             )
                             vc_created_count += 1
                             log_msg = f"Created VC '{vc.name}' during bulk import for device {device_id}"
@@ -227,6 +306,7 @@ def bulk_import_devices_shared(
         "failed": failed_list,
         "skipped": skipped_list,
         "virtual_chassis_created": vc_created_count,
+        "cancelled": _cancelled,
     }
 
 
@@ -236,6 +316,7 @@ def bulk_import_devices(
     sync_options: dict = None,
     manual_mappings_per_device: dict = None,
     libre_devices_cache: dict = None,
+    vc_detection_enabled: bool = False,
     user=None,
 ) -> dict:
     """
@@ -252,6 +333,7 @@ def bulk_import_devices(
             Example: {1179: {'device_role_id': 5}, 1180: {'device_role_id': 3}}
         libre_devices_cache: Optional dict mapping device_id to pre-fetched device data
             to avoid redundant API calls. Example: {123: {...device_data...}}
+        vc_detection_enabled: Whether to enable virtual chassis detection during import.
         user: User performing the import (for permission checks)
 
     Returns:
@@ -273,50 +355,127 @@ def bulk_import_devices(
         sync_options=sync_options,
         manual_mappings_per_device=manual_mappings_per_device,
         libre_devices_cache=libre_devices_cache,
+        vc_detection_enabled=vc_detection_enabled,
         job=None,  # No job context for synchronous imports
         user=user,
     )
 
 
-def _refresh_existing_device(validation: dict) -> None:
-    """Refresh existing_device from DB to pick up changes made in NetBox since caching."""
+def _refresh_existing_device(validation: dict, libre_device: dict = None, server_key: str = "default") -> None:
+    """
+    Refresh existing_device from DB to pick up changes made in NetBox since caching.
+
+    When existing_device is None (wasn't found at cache time), re-check if the device
+    was imported since caching by looking up librenms_id or hostname.
+    """
     existing = validation.get("existing_device")
-    if not existing or not hasattr(existing, "pk"):
+    if existing and hasattr(existing, "pk"):
+        try:
+            from dcim.models import Device
+            from virtualization.models import VirtualMachine
+
+            if validation.get("import_as_vm"):
+                refreshed = VirtualMachine.objects.filter(pk=existing.pk).first()
+            else:
+                refreshed = Device.objects.filter(pk=existing.pk).first()
+
+            if refreshed:
+                validation["existing_device"] = refreshed
+                if hasattr(refreshed, "role") and refreshed.role:
+                    apply_role_to_validation(validation, refreshed.role, is_vm=bool(validation.get("import_as_vm")))
+                elif not validation.get("import_as_vm"):
+                    apply_role_to_validation(validation, None)
+                recalculate_validation_status(validation, is_vm=bool(validation.get("import_as_vm")))
+                return
+            else:
+                # Device was deleted since caching — recompute readiness to match
+                # validate_device_for_import logic.
+                validation["existing_device"] = None
+                validation["existing_match_type"] = None
+                # Clear stale device_role so is_ready is computed from scratch.
+                # Guard: VMs don't use device_role for readiness, so preserve any
+                # user-selected role rather than silently dropping it.
+                if not validation.get("import_as_vm"):
+                    validation["device_role"] = {"found": False, "role": None}
+                recalculate_validation_status(validation, is_vm=bool(validation.get("import_as_vm")))
+        except Exception as e:
+            existing_id = getattr(existing, "pk", "unknown") if existing else "none"
+            logger.error(f"Failed to refresh existing device (pk={existing_id}): {e}")
+        return
+
+    # existing_device was None at cache time — check if device was imported since
+    if not libre_device:
         return
     try:
         from dcim.models import Device
         from virtualization.models import VirtualMachine
 
-        if validation.get("import_as_vm"):
-            refreshed = VirtualMachine.objects.filter(pk=existing.pk).first()
-        else:
-            refreshed = Device.objects.filter(pk=existing.pk).first()
+        import_as_vm = validation.get("import_as_vm", False)
+        Model = VirtualMachine if import_as_vm else Device
+        # Also check the opposite model — the LibreNMS object may have been
+        # imported as a VM even though import_as_vm=False (or vice versa).
+        CrossModel = Device if import_as_vm else VirtualMachine
 
-        if refreshed:
-            validation["existing_device"] = refreshed
-            if hasattr(refreshed, "role") and refreshed.role:
-                validation["device_role"]["found"] = True
-                validation["device_role"]["role"] = refreshed.role
-        else:
-            # Device was deleted since caching — recompute readiness
-            validation["existing_device"] = None
-            validation["existing_match_type"] = None
-            if validation.get("import_as_vm"):
-                required_found = (
-                    validation.get("site", {}).get("found")
-                    and validation.get("cluster", {}).get("found")
-                    and validation.get("device_role", {}).get("found")
-                )
-            else:
-                required_found = (
-                    validation.get("site", {}).get("found")
-                    and validation.get("device_type", {}).get("found")
-                    and validation.get("device_role", {}).get("found")
-                )
-            validation["can_import"] = validation["is_ready"] = bool(required_found and not validation.get("issues"))
+        librenms_id = libre_device.get("device_id")
+        hostname = libre_device.get("hostname", "")
+        sys_name = libre_device.get("sysName", "")
+
+        new_device = None
+        match_type = None
+        found_as_cross_model = False
+
+        def _lookup_in_model(m):
+            """Return (device, match_type) for model m, or (None, None)."""
+            if librenms_id is not None and not isinstance(librenms_id, bool):
+                try:
+                    dev = find_by_librenms_id(m, int(librenms_id), server_key)
+                    if dev:
+                        return dev, "librenms_id"
+                except (ValueError, TypeError):
+                    pass
+            resolved_name = validation.get("resolved_name")
+            if resolved_name:
+                dev = m.objects.filter(name__iexact=resolved_name).first()
+                if dev:
+                    return dev, "resolved_name"
+            if hostname:
+                dev = m.objects.filter(name__iexact=hostname).first()
+                if dev:
+                    return dev, "hostname"
+            if sys_name:
+                dev = m.objects.filter(name__iexact=sys_name).first()
+                if dev:
+                    return dev, "sysname"
+            return None, None
+
+        new_device, match_type = _lookup_in_model(Model)
+
+        if not new_device:
+            # Try the opposite model: catches cross-model imports that happened
+            # after the cache was built (e.g. LibreNMS device imported as VM).
+            new_device, match_type = _lookup_in_model(CrossModel)
+            if new_device:
+                found_as_cross_model = True
+
+        if new_device:
+            validation["existing_device"] = new_device
+            validation["existing_match_type"] = match_type
+            validation["can_import"] = False
+            validation["is_ready"] = False
+            # Determine actual model from the found object, not from import_as_vm flag
+            actual_is_vm = found_as_cross_model != import_as_vm  # XOR: cross flips the flag
+            validation["import_as_vm"] = actual_is_vm  # Update so future refreshes query correct model
+            if not actual_is_vm and hasattr(new_device, "role") and new_device.role:
+                validation["device_role"] = {"found": True, "role": new_device.role}
+            elif not actual_is_vm:
+                validation.setdefault("device_role", {}).update({"found": False, "role": None})
     except Exception as e:
-        existing_id = getattr(existing, "pk", "unknown") if existing else "none"
-        logger.error(f"Failed to refresh existing device (pk={existing_id}): {e}")
+        logger.error(f"Failed to check for newly imported device: {e}")
+
+
+def _empty_return(return_cache_status: bool):
+    """Centralised empty-result return value for process_device_filters."""
+    return ([], False) if return_cache_status else []
 
 
 def process_device_filters(
@@ -350,7 +509,7 @@ def process_device_filters(
         request: Optional Django request for client disconnect detection (synchronous only)
         return_cache_status: When True, returns (devices, from_cache) tuple
         use_sysname: If True, prefer sysName over hostname for device name resolution
-        strip_domain: If True, strip domain suffix from device names
+        strip_domain: If True, strip domain suffix from device name
 
     Returns:
         List[dict]: Validated devices with _validation key, or tuple of (devices, from_cache)
@@ -372,9 +531,11 @@ def process_device_filters(
         return_cache_status=True,
     )
 
-    # Filter out disabled devices if requested
+    # Filter out disabled devices if requested. LibreNMS's "disabled" field (1=disabled,
+    # 0=enabled) reflects manual device disablement; "status" reflects SNMP reachability.
+    # show_disabled controls the former: hidden when disabled==1, shown regardless of status.
     if not show_disabled:
-        libre_devices = [d for d in libre_devices if d.get("status") == 1]
+        libre_devices = [d for d in libre_devices if _safe_disabled(d) != 1]
 
     if job:
         job.logger.info(f"Found {len(libre_devices)} devices to process")
@@ -398,13 +559,14 @@ def process_device_filters(
         except (BrokenPipeError, ConnectionError, IOError) as e:
             if request:
                 logger.info(f"Client disconnected during VC prefetch: {e}")
-                return []
+                return _empty_return(return_cache_status)
             raise
 
     # Validate each device
     validated_devices = []
     total = len(libre_devices)
-    api_for_validation = api if vc_detection_enabled else None
+    # Always pass api so validate_device_for_import can run hardware/chassis lookups.
+    # vc_detection_enabled only gates VC-specific paths inside that function.
 
     if job:
         job.logger.info(f"Starting validation of {total} devices")
@@ -418,13 +580,13 @@ def process_device_filters(
 
             if rq_job.is_failed or rq_job.is_stopped:
                 job.logger.warning("Job was already stopped before validation started")
-                return []
+                return _empty_return(return_cache_status)
         except Exception:
             # Fall back to DB check if RQ check fails
             job.job.refresh_from_db()
-            if job.job.status == JobStatusChoices.STATUS_FAILED:
+            if job.job.status in (JobStatusChoices.STATUS_FAILED, JobStatusChoices.STATUS_ERRORED):
                 job.logger.warning("Job was stopped before validation started")
-                return []
+                return _empty_return(return_cache_status)
     else:
         logger.info(f"Validating {total} devices")
 
@@ -447,21 +609,13 @@ def process_device_filters(
                         job.logger.info(
                             f"Job stopped at device {idx}/{total} (RQ status: {rq_job.get_status()}). Exiting gracefully."
                         )
-                        return []
+                        return _empty_return(return_cache_status)
                 except Exception:
                     # If we can't check RQ status, fall back to DB status check
                     job.job.refresh_from_db()
-                    if job.job.status == JobStatusChoices.STATUS_FAILED:
+                    if job.job.status in (JobStatusChoices.STATUS_FAILED, JobStatusChoices.STATUS_ERRORED):
                         job.logger.info(f"Job stopped at device {idx}/{total}. Exiting gracefully.")
-                        return []
-            elif request:
-                # Check for client disconnect
-                try:
-                    if hasattr(request, "META") and request.META.get("wsgi.input"):
-                        pass
-                except (BrokenPipeError, ConnectionError, IOError):
-                    logger.info(f"Client disconnected during validation at device {idx}")
-                    return []
+                        return _empty_return(return_cache_status)
 
         # Drop any cached validation/meta keys before recomputing
         device.pop("_validation", None)
@@ -487,7 +641,7 @@ def process_device_filters(
 
                 # Refresh existing_device from DB to avoid stale data
                 # (user may have changed role, name, etc. in NetBox)
-                _refresh_existing_device(device["_validation"])
+                _refresh_existing_device(device["_validation"], libre_device=device, server_key=api.server_key)
 
                 # Apply exclude_existing filter if enabled
                 if exclude_existing:
@@ -502,16 +656,17 @@ def process_device_filters(
         try:
             validation = validate_device_for_import(
                 device,
-                api=api_for_validation,
+                api=api,
                 include_vc_detection=vc_detection_enabled,
-                force_vc_refresh=clear_cache,
+                force_vc_refresh=False,
+                server_key=api.server_key,
                 use_sysname=use_sysname,
                 strip_domain=strip_domain,
             )
         except (BrokenPipeError, ConnectionError, IOError) as e:
             if request:
                 logger.info(f"Client disconnected during device validation: {e}")
-                return []
+                return _empty_return(return_cache_status)
             raise
 
         # Set VC detection metadata
@@ -577,8 +732,10 @@ def process_device_filters(
             # Add this cache key if not already in index
             if cache_metadata_key not in cache_index:
                 cache_index.append(cache_metadata_key)
-                # Store index with same timeout as the metadata
-                cache.set(cache_index_key, cache_index, timeout=api.cache_timeout)
+            # Always re-write the index so its TTL matches the freshly-written metadata.
+            # Without this the index can expire before the metadata and the active
+            # search entry disappears from the UI.
+            cache.set(cache_index_key, cache_index, timeout=api.cache_timeout)
 
     if job:
         if exclude_existing:
diff --git a/netbox_librenms_plugin/import_utils/cache.py b/netbox_librenms_plugin/import_utils/cache.py
index 81fb8f7e32..8de881f897 100644
--- a/netbox_librenms_plugin/import_utils/cache.py
+++ b/netbox_librenms_plugin/import_utils/cache.py
@@ -1,5 +1,7 @@
-"""Cache key generation and search management for device import operations."""
+"""Cache key generation and management for device import operations."""
 
+import hashlib
+import json
 import logging
 
 from django.core.cache import cache
@@ -7,6 +9,11 @@
 logger = logging.getLogger(__name__)
 
 
+def get_location_choices_cache_key(server_key: str) -> str:
+    """Return the cache key for LibreNMS location choices for a given server."""
+    return f"librenms_locations_choices:{server_key}"
+
+
 def get_cache_metadata_key(
     server_key: str, filters: dict, vc_enabled: bool, use_sysname: bool = True, strip_domain: bool = False
 ) -> str:
@@ -17,16 +24,22 @@ def get_cache_metadata_key(
         server_key: LibreNMS server identifier
         filters: Filter dictionary
         vc_enabled: Whether VC detection is enabled
-        use_sysname: Whether sysName is preferred for device name resolution
+        use_sysname: Whether sysName is preferred over hostname for device naming
         strip_domain: Whether domain suffix is stripped from device names
 
     Returns:
         str: Consistent cache key for metadata
     """
-    # Sort filter items to ensure consistent key generation
-    filter_parts = "_".join(f"{k}={v}" for k, v in sorted(filters.items()) if v)
-    naming_part = f"sysname{int(use_sysname)}_strip{int(strip_domain)}"
-    return f"librenms_filter_cache_metadata_{server_key}_{filter_parts}_{vc_enabled}_{naming_part}"
+    # Sort filter items to ensure consistent key generation; use "is not None" to preserve
+    # valid falsy values like 0 and False (filtering only None/missing entries).
+    # Use JSON serialization for a stable, collision-free hash (avoids issues with
+    # values containing "=" or "_" that could collide with the key separators).
+    filter_hash = hashlib.sha256(
+        json.dumps(
+            {k: v for k, v in sorted(filters.items()) if v is not None}, sort_keys=True, separators=(",", ":")
+        ).encode()
+    ).hexdigest()[:16]
+    return f"librenms_filter_cache_metadata_{server_key}_{filter_hash}_{vc_enabled}_sysname={use_sysname}_strip={strip_domain}"
 
 
 def get_active_cached_searches(server_key: str) -> list[dict]:
@@ -66,8 +79,9 @@ def get_active_cached_searches(server_key: str) -> list[dict]:
         "other": "Other",
     }
 
-    # Get cached location choices for enrichment
-    location_cache_key = "librenms_locations_choices"
+    # Get cached location choices for enrichment; scoped by server_key so labels
+    # from different LibreNMS servers don't bleed into each other's filter summaries.
+    location_cache_key = get_location_choices_cache_key(server_key)
     cached_locations = cache.get(location_cache_key)
     if cached_locations:
         location_choices = dict(cached_locations)
@@ -76,9 +90,18 @@ def get_active_cached_searches(server_key: str) -> list[dict]:
         metadata = cache.get(cache_key)
         if metadata:
             # Cache still exists, calculate time remaining
-            cached_at = datetime.fromisoformat(metadata.get("cached_at"))
             cache_timeout = metadata.get("cache_timeout", 300)
             now = datetime.now(timezone.utc)
+            try:
+                cached_at_raw = metadata.get("cached_at")
+                cached_at = (
+                    datetime.fromisoformat(cached_at_raw) if cached_at_raw else datetime.fromtimestamp(0, timezone.utc)
+                )
+                # Normalize naive datetimes (e.g., stored without tzinfo) to UTC
+                if cached_at.tzinfo is None:
+                    cached_at = cached_at.replace(tzinfo=timezone.utc)
+            except (ValueError, TypeError):
+                cached_at = datetime.fromtimestamp(0, timezone.utc)
             age_seconds = (now - cached_at).total_seconds()
             remaining_seconds = max(0, cache_timeout - age_seconds)
 
@@ -133,7 +156,7 @@ def get_validated_device_cache_key(
         filters: Filter dict with location, type, os, hostname, sysname, hardware keys
         device_id: LibreNMS device ID
         vc_enabled: Whether virtual chassis detection was enabled
-        use_sysname: Whether sysName is preferred for device name resolution
+        use_sysname: Whether sysName is preferred over hostname for device naming
         strip_domain: Whether domain suffix is stripped from device names
 
     Returns:
@@ -142,16 +165,17 @@ def get_validated_device_cache_key(
     Example:
         >>> key = get_validated_device_cache_key('default', {'location': 'NYC'}, 123, True)
         >>> key
-        'validated_device_default_-1234567890_123_vc_sysname1_strip0'
+        'validated_device_default_e3b0c44298fc1c14_123_vc'
     """
-    # Sort filters for consistent hashing
-    filter_hash = hash(str(sorted(filters.items())))
+    # Sort filters for a deterministic, cross-process stable hash
+    filter_hash = hashlib.sha256(json.dumps(sorted(filters.items()), sort_keys=True).encode()).hexdigest()[:16]
     vc_part = "vc" if vc_enabled else "novc"
-    naming_part = f"sysname{int(use_sysname)}_strip{int(strip_domain)}"
-    return f"validated_device_{server_key}_{filter_hash}_{device_id}_{vc_part}_{naming_part}"
+    return (
+        f"validated_device_{server_key}_{filter_hash}_{device_id}_{vc_part}_sysname={use_sysname}_strip={strip_domain}"
+    )
 
 
-def get_import_device_cache_key(device_id: int | str, server_key: str = "default") -> str:
+def get_import_device_cache_key(device_id: int | str, server_key: str) -> str:
     """
     Generate cache key for raw LibreNMS device data.
 
@@ -161,7 +185,7 @@ def get_import_device_cache_key(device_id: int | str, server_key: str = "default
 
     Args:
         device_id: LibreNMS device ID
-        server_key: LibreNMS server identifier for multi-server setups
+        server_key: LibreNMS server identifier for multi-server setups (required)
 
     Returns:
         str: Cache key for the device data
@@ -171,3 +195,29 @@ def get_import_device_cache_key(device_id: int | str, server_key: str = "default
         'import_device_data_production_123'
     """
     return f"import_device_data_{server_key}_{device_id}"
+
+
+def get_import_search_cache_key(server_key: str, api_filters: dict, client_filters: dict) -> str:
+    """
+    Generate a deterministic cache key for a LibreNMS device search result.
+
+    The key encodes the server, API-side filters, and client-side filters so
+    that different filter combinations produce distinct cache entries.
+
+    Args:
+        server_key: Resolved LibreNMS server key (use ``api.server_key``).
+        api_filters: Filters forwarded to the LibreNMS API.
+        client_filters: Filters applied client-side after the API response.
+
+    Returns:
+        str: Cache key for the import search result.
+    """
+    import hashlib
+    import json
+
+    def _hash(d):
+        return hashlib.sha256(
+            json.dumps(sorted(d.items()) if isinstance(d, dict) else d, sort_keys=True).encode()
+        ).hexdigest()[:16]
+
+    return f"librenms_devices_import_{server_key}_{_hash(api_filters)}_{_hash(client_filters)}"
diff --git a/netbox_librenms_plugin/import_utils/device_operations.py b/netbox_librenms_plugin/import_utils/device_operations.py
index 608cc42927..551449c334 100644
--- a/netbox_librenms_plugin/import_utils/device_operations.py
+++ b/netbox_librenms_plugin/import_utils/device_operations.py
@@ -14,6 +14,7 @@
     find_matching_platform,
     find_matching_site,
     match_librenms_hardware_to_device_type,
+    set_librenms_device_id,
 )
 from .cache import get_import_device_cache_key
 from .virtual_chassis import (
@@ -48,7 +49,6 @@ def _try_chassis_device_type_match(api, device_id):
         if not success or not inventory:
             return None
 
-        first_ambiguous_model = None
         for item in inventory:
             # Try entPhysicalName first (often the chassis part number like CHAS-BP-MX480-S)
             for field in ("entPhysicalName", "entPhysicalModelName"):
@@ -56,9 +56,6 @@ def _try_chassis_device_type_match(api, device_id):
                 if value and value not in skip_values:
                     chassis_match = match_librenms_hardware_to_device_type(value)
                     if chassis_match is None:
-                        # MultipleObjectsReturned — ambiguous match; remember first
-                        if first_ambiguous_model is None:
-                            first_ambiguous_model = value
                         continue
                     if chassis_match["matched"]:
                         chassis_match["match_type"] = "chassis"
@@ -66,15 +63,7 @@ def _try_chassis_device_type_match(api, device_id):
                         return chassis_match
     except Exception:
         logger.debug(f"Chassis inventory fallback failed for device {device_id}", exc_info=True)
-        return None
 
-    if first_ambiguous_model is not None:
-        return {
-            "matched": False,
-            "device_type": None,
-            "match_type": "chassis_ambiguous",
-            "chassis_model": first_ambiguous_model,
-        }
     return None
 
 
@@ -143,6 +132,7 @@ def validate_device_for_import(
     force_vc_refresh: bool = False,
     use_sysname: bool = True,
     strip_domain: bool = False,
+    server_key: str = "default",
 ) -> dict:
     """
     Validate if a LibreNMS device can be imported to NetBox.
@@ -217,6 +207,7 @@ def validate_device_for_import(
         "serial_action": None,  # None, "link", "conflict", "update_serial", "hostname_differs"
         "serial_confirmed": False,  # True when librenms_id match and serial matches
         "serial_duplicate": False,  # True when incoming serial is already on a different device
+        "librenms_id_needs_migration": False,  # True when existing device has legacy bare-int ID
         "name_matches": False,  # True when existing device name matches LibreNMS sysName
         "name_sync_available": False,  # True when existing device name differs from sysName
         "suggested_name": None,  # sysName to suggest when name_sync_available is True
@@ -289,10 +280,13 @@ def validate_device_for_import(
 
         from virtualization.models import VirtualMachine
 
+        server_key = api.server_key if api is not None else server_key
+
         # Check for existing VM first (by librenms_id custom field)
-        # Always query with int to match custom field type
         try:
-            existing_vm = VirtualMachine.objects.filter(custom_field_data__librenms_id=int(librenms_id)).first()
+            from netbox_librenms_plugin.utils import find_by_librenms_id
+
+            existing_vm = find_by_librenms_id(VirtualMachine, librenms_id, server_key)
         except (ValueError, TypeError):
             # librenms_id is not convertible to int; no match will be found
             existing_vm = None
@@ -304,7 +298,17 @@ def validate_device_for_import(
             result["import_as_vm"] = True  # Force VM mode since VM exists
             result["can_import"] = False
 
-            # Check if name matches sysName
+            # Detect legacy bare-integer or string-digit format so UI can offer a migration action.
+            # Direct access needed to detect legacy format for migration prompt:
+            # LibreNMSAPI.get_librenms_id() returns an int in both formats, so only the
+            # raw type check on custom_field_data reveals whether migration is needed.
+            _vm_cf_id = existing_vm.custom_field_data.get("librenms_id")
+            if (isinstance(_vm_cf_id, int) and not isinstance(_vm_cf_id, bool)) or (
+                isinstance(_vm_cf_id, str) and _vm_cf_id.isdigit()
+            ):
+                result["librenms_id_needs_migration"] = True
+
+            # Check if name matches resolved name (accounts for use_sysname/strip_domain)
             # Note: name_sync_available/suggested_name are intentionally not set for VMs
             # because UpdateDeviceNameView only supports Device objects; VM name-sync
             # would require a separate implementation.
@@ -312,10 +316,11 @@ def validate_device_for_import(
                 result["name_matches"] = True
 
         # Check for existing Device (by librenms_id custom field)
-        # Always query with int to match custom field type
         if not result["existing_device"]:
             try:
-                existing_device = Device.objects.filter(custom_field_data__librenms_id=int(librenms_id)).first()
+                from netbox_librenms_plugin.utils import find_by_librenms_id
+
+                existing_device = find_by_librenms_id(Device, librenms_id, server_key)
             except (ValueError, TypeError):
                 # librenms_id is not convertible to int; no match will be found
                 existing_device = None
@@ -326,6 +331,16 @@ def validate_device_for_import(
                 result["existing_match_type"] = "librenms_id"
                 result["can_import"] = False
 
+                # Detect legacy bare-integer or string-digit format so UI can offer a migration action.
+                # Direct access needed to detect legacy format for migration prompt:
+                # LibreNMSAPI.get_librenms_id() returns an int in both formats, so only the
+                # raw type check on custom_field_data reveals whether migration is needed.
+                _dev_cf_id = existing_device.custom_field_data.get("librenms_id")
+                if (isinstance(_dev_cf_id, int) and not isinstance(_dev_cf_id, bool)) or (
+                    isinstance(_dev_cf_id, str) and _dev_cf_id.isdigit()
+                ):
+                    result["librenms_id_needs_migration"] = True
+
                 # Check if name matches resolved name (VC-aware: compare against VC member name)
                 if hostname and existing_device.virtual_chassis and existing_device.vc_position:
                     incoming_serial = libre_device.get("serial") or ""
@@ -481,11 +496,8 @@ def validate_device_for_import(
 
         # Validate based on import type (Device or VM)
         if import_as_vm:
-            # 2. For VMs: Validate Cluster (required) - Must be manually selected
-            result["cluster"]["found"] = False
-            if not result.get("existing_device"):
-                result["issues"].append("Cluster must be manually selected before importing as VM")
-            # Provide list of available clusters for user selection (cached)
+            # Always populate available clusters for all VMs (new or existing) so
+            # the cluster dropdown has options whether creating or updating a VM.
             cache_key = "librenms_import_all_clusters"
             all_clusters = cache.get(cache_key)
             if all_clusters is None:
@@ -495,7 +507,13 @@ def validate_device_for_import(
                 cache.set(cache_key, all_clusters, cache_timeout)
             result["cluster"]["available_clusters"] = all_clusters
 
-            # Skip device-specific validations for VMs
+        if import_as_vm:
+            if not result.get("existing_device"):
+                # 2. For NEW VMs: Validate Cluster (required) - Must be manually selected
+                result["cluster"]["found"] = False
+                result["issues"].append("Cluster must be manually selected before importing as VM")
+
+            # Skip device-specific validations for all VMs (new and existing)
             result["site"]["found"] = True  # Not required for VMs
             result["device_type"]["found"] = True  # Not required for VMs
             result["device_role"]["found"] = True  # Not required for VMs
@@ -533,18 +551,6 @@ def validate_device_for_import(
                         chassis_match = _try_chassis_device_type_match(api, device_id)
                         if chassis_match and chassis_match["matched"]:
                             dt_match = chassis_match
-                        elif chassis_match and chassis_match.get("match_type") == "chassis_ambiguous":
-                            # Chassis inventory returned multiple matches — propagate ambiguity
-                            dt_match = {
-                                "matched": False,
-                                "device_type": None,
-                                "match_type": "ambiguous",
-                            }
-                            result["issues"].append(
-                                f"Multiple device types match chassis hardware"
-                                f" '{chassis_match['chassis_model']}'"
-                                " — resolve the ambiguity in NetBox."
-                            )
 
                 # Update result keys individually to preserve the existing schema (especially "found")
                 result["device_type"]["found"] = dt_match["matched"]
@@ -552,6 +558,7 @@ def validate_device_for_import(
                 result["device_type"]["match_type"] = dt_match.get("match_type")
 
             if not result["device_type"]["found"] and result["device_type"].get("match_type") != "ambiguous":
+                result["device_type"]["found"] = False
                 result["issues"].append(f"No matching device type found for hardware: '{hardware}'")
                 # Get some device types for user to choose from
                 all_device_types = DeviceType.objects.all()[:10]
@@ -564,12 +571,12 @@ def validate_device_for_import(
                     for dt in all_device_types
                 ]
 
-            # 4. DeviceRole (required) - Must be manually selected by user
-            logger.debug(f"[{hostname}] Issues BEFORE adding role issue: {result['issues']}")
-            result["device_role"]["found"] = False
             if not result.get("existing_device"):
+                # 4. DeviceRole (required for new devices) - Must be manually selected
+                logger.debug(f"[{hostname}] Issues BEFORE adding role issue: {result['issues']}")
+                result["device_role"]["found"] = False
                 result["issues"].append("Device role must be manually selected before import")
-            logger.debug(f"[{hostname}] Issues AFTER adding role issue: {result['issues']}")
+                logger.debug(f"[{hostname}] Issues AFTER adding role issue: {result['issues']}")
             # Provide list of available roles for user selection (cached)
             cache_key = "librenms_import_all_roles"
             all_roles = cache.get(cache_key)
@@ -761,6 +768,7 @@ def import_single_device(
                 api=api,
                 use_sysname=use_sysname_opt,
                 strip_domain=strip_domain_opt,
+                server_key=api.server_key,
             )
 
         # Check if device already exists
@@ -795,8 +803,6 @@ def import_single_device(
             if rack_id:
                 rack = Rack.objects.select_related("location", "site").filter(id=rack_id).first() or rack
 
-        rack = rack or validation.get("rack", {}).get("rack")
-
         # Validate required fields
         if not site:
             return {
@@ -825,16 +831,20 @@ def import_single_device(
 
         # Create device in NetBox
         with transaction.atomic():
-            # Determine device name based on sync options
-            use_sysname = sync_options.get("use_sysname", True) if sync_options else True
-            strip_domain = sync_options.get("strip_domain", False) if sync_options else False
-
-            device_name = _determine_device_name(
-                libre_device,
-                use_sysname=use_sysname,
-                strip_domain=strip_domain,
-                device_id=device_id,
-            )
+            # Use pre-computed resolved_name from validation when available so the
+            # created device name matches exactly what was displayed in the import UI.
+            # Only fall back to recomputing from sync_options when no validation exists.
+            if validation and validation.get("resolved_name"):
+                device_name = validation["resolved_name"]
+            else:
+                use_sysname = sync_options.get("use_sysname", True) if sync_options else True
+                strip_domain = sync_options.get("strip_domain", False) if sync_options else False
+                device_name = _determine_device_name(
+                    libre_device,
+                    use_sysname=use_sysname,
+                    strip_domain=strip_domain,
+                    device_id=device_id,
+                )
 
             # Generate import timestamp comment
             import_time = timezone.now().strftime("%Y-%m-%d %H:%M:%S %Z")
@@ -846,7 +856,6 @@ def import_single_device(
                 "role": device_role,
                 "status": "active" if libre_device.get("status") == 1 else "offline",
                 "comments": f"Imported from LibreNMS by netbox-librenms-plugin on {import_time}",
-                "custom_field_data": {"librenms_id": int(device_id)},
             }
 
             # Add optional fields
@@ -871,6 +880,7 @@ def import_single_device(
 
             # Create the device
             device = Device(**device_data)
+            set_librenms_device_id(device, device_id, api.server_key)
             device.full_clean()
             device.save()
 
diff --git a/netbox_librenms_plugin/import_utils/filters.py b/netbox_librenms_plugin/import_utils/filters.py
index 99aae78d5d..bdee6da79d 100644
--- a/netbox_librenms_plugin/import_utils/filters.py
+++ b/netbox_librenms_plugin/import_utils/filters.py
@@ -1,15 +1,40 @@
-"""Device filtering and API queries for LibreNMS devices."""
+"""Device filtering and retrieval from LibreNMS."""
 
 import logging
 from typing import List
 
 from django.core.cache import cache
 
+from .cache import get_import_search_cache_key
+
 from ..librenms_api import LibreNMSAPI
 
 logger = logging.getLogger(__name__)
 
 
+def _safe_disabled(device: dict) -> int:
+    """
+    Return 1 if the device is disabled, 0 otherwise.
+
+    Handles None, booleans, numeric strings, and common truthy/falsy tokens
+    (e.g. "true"/"yes"/"on" → 1, "false"/"no"/"off" → 0) without raising.
+    """
+    val = device.get("disabled", 0)
+    if isinstance(val, bool):
+        return int(val)
+    if isinstance(val, str):
+        normalized = val.strip().lower()
+        if normalized in ("1", "true", "yes", "on"):
+            return 1
+        if normalized in ("0", "false", "no", "off", ""):
+            return 0
+    try:
+        int_val = int(val)
+        return 1 if int_val else 0
+    except (TypeError, ValueError):
+        return 0
+
+
 def get_device_count_for_filters(
     api: LibreNMSAPI,
     filters: dict,
@@ -33,9 +58,11 @@ def get_device_count_for_filters(
     """
     devices = get_librenms_devices_for_import(api, filters=filters, force_refresh=clear_cache)
 
-    # Filter out disabled devices if requested
+    # Filter out disabled devices if requested. LibreNMS's "disabled" field (1=disabled,
+    # 0=enabled) reflects manual device disablement; "status" reflects SNMP reachability.
+    # show_disabled controls the former: hidden when disabled==1, shown regardless of status.
     if not show_disabled:
-        devices = [d for d in devices if d.get("status") == 1]
+        devices = [d for d in devices if _safe_disabled(d) != 1]
 
     return len(devices)
 
@@ -85,10 +112,15 @@ def get_librenms_devices_for_import(
         if filters:
             # Check for status filter first - it has special handling
             if filters.get("status") is not None:
+                # Normalize to int: form fields send strings ("1"/"0"), API may send ints
+                try:
+                    status_val = int(filters["status"])
+                except (ValueError, TypeError):
+                    status_val = None
                 # Status filter uses special types that don't need query param
-                if filters["status"] == 1:
+                if status_val == 1:
                     api_filters["type"] = "up"
-                elif filters["status"] == 0:
+                elif status_val == 0:
                     api_filters["type"] = "down"
 
                 # Save ALL other filters for client-side filtering when status is used
@@ -170,8 +202,9 @@ def get_librenms_devices_for_import(
             # We'll filter client-side if needed
 
         # Use caching to avoid repeated API calls
-        # Include both API and client filters in cache key
-        cache_key = f"librenms_devices_import_{server_key}_{hash(str(api_filters))}_{hash(str(client_filters))}"
+        # Include both API and client filters in cache key (deterministic, cross-process stable).
+        # Use api.server_key (always resolved) rather than the raw server_key arg (may differ).
+        cache_key = get_import_search_cache_key(api.server_key, api_filters, client_filters)
         from_cache = False
 
         if force_refresh:
@@ -190,6 +223,8 @@ def get_librenms_devices_for_import(
 
         if not success:
             logger.error(f"Failed to retrieve devices from LibreNMS: {devices}")
+            # Cache a brief negative result to prevent hammering the API on repeated failures.
+            cache.set(cache_key, [], timeout=min(60, api.cache_timeout))
             if return_cache_status:
                 return [], False
             return []
@@ -232,19 +267,19 @@ def _apply_client_filters(devices: List[dict], filters: dict) -> List[dict]:
 
     if filters.get("type"):
         device_type = filters["type"].lower()
-        filtered = [d for d in filtered if d.get("type", "").lower() == device_type]
+        filtered = [d for d in filtered if (d.get("type") or "").lower() == device_type]
 
     if filters.get("os"):
         os_filter = filters["os"].lower()
-        filtered = [d for d in filtered if os_filter in d.get("os", "").lower()]
+        filtered = [d for d in filtered if os_filter in (d.get("os") or "").lower()]
 
     if filters.get("hostname"):
         hostname_filter = filters["hostname"].lower()
-        filtered = [d for d in filtered if hostname_filter in d.get("hostname", "").lower()]
+        filtered = [d for d in filtered if hostname_filter in (d.get("hostname") or "").lower()]
 
     if filters.get("sysname"):
         sysname_filter = filters["sysname"].lower()
-        filtered = [d for d in filtered if sysname_filter in d.get("sysName", "").lower()]
+        filtered = [d for d in filtered if sysname_filter in (d.get("sysName") or "").lower()]
 
     if filters.get("hardware"):
         hardware_filter = filters["hardware"].lower()
diff --git a/netbox_librenms_plugin/import_utils/virtual_chassis.py b/netbox_librenms_plugin/import_utils/virtual_chassis.py
index da1d0db897..f7a1a58b78 100644
--- a/netbox_librenms_plugin/import_utils/virtual_chassis.py
+++ b/netbox_librenms_plugin/import_utils/virtual_chassis.py
@@ -1,4 +1,4 @@
-"""Virtual chassis detection, creation, and caching."""
+"""Virtual chassis detection, creation, and management."""
 
 import logging
 from typing import List
@@ -32,11 +32,12 @@ def _clone_virtual_chassis_data(data: dict | None) -> dict:
     members = []
     for idx, member in enumerate(data.get("members", [])):
         member_copy = member.copy()
-        raw_position = member_copy.get("position", idx)
+        raw_position = member_copy.get("position", idx + 1)
         try:
-            member_copy["position"] = int(raw_position)
+            pos = int(raw_position)
+            member_copy["position"] = pos if pos > 0 else idx + 1
         except (TypeError, ValueError):
-            member_copy["position"] = idx
+            member_copy["position"] = idx + 1  # 1-based fallback; position 0 is invalid
         members.append(member_copy)
 
     member_count = data.get("member_count") or len(members)
@@ -64,19 +65,29 @@ def get_virtual_chassis_data(api: LibreNMSAPI, device_id: int | str, *, force_re
         return empty_virtual_chassis_data()
 
     cache_key = _vc_cache_key(api, device_id)
-    if not force_refresh:
+    _cache_timeout = getattr(api, "cache_timeout", None)
+    cache_timeout = 300 if _cache_timeout is None else _cache_timeout
+    if not force_refresh and cache_timeout != 0:
         cached = cache.get(cache_key)
         if cached is not None:
             return _clone_virtual_chassis_data(cached)
 
     detection_data = detect_virtual_chassis_from_inventory(api, device_id)
-    if detection_data and "detection_error" not in detection_data:
+    if detection_data is None:
+        # Non-stack device or transient API failure — cache the negative result so
+        # prefetch_vc_data_for_devices() can skip these on subsequent renders.
+        # Use force_refresh=True to bypass the cache if needed.
+        empty = empty_virtual_chassis_data()
+        if cache_timeout != 0:
+            cache.set(cache_key, empty, timeout=cache_timeout)
+        return _clone_virtual_chassis_data(empty)
+
+    if "detection_error" not in detection_data:
         detection_data["detection_error"] = None
 
-    cache_value = _clone_virtual_chassis_data(detection_data) if detection_data else empty_virtual_chassis_data()
-
-    cache_timeout = getattr(api, "cache_timeout", 300) or 300
-    cache.set(cache_key, cache_value, timeout=cache_timeout)
+    cache_value = _clone_virtual_chassis_data(detection_data)
+    if cache_timeout != 0:
+        cache.set(cache_key, cache_value, timeout=cache_timeout)
     return _clone_virtual_chassis_data(cache_value)
 
 
@@ -117,7 +128,7 @@ def prefetch_vc_data_for_devices(api: LibreNMSAPI, device_ids: List[int], *, for
     logger.debug(f"VC cache warming complete for {len(device_ids)} devices")
 
 
-def detect_virtual_chassis_from_inventory(api: LibreNMSAPI, device_id: int) -> dict:
+def detect_virtual_chassis_from_inventory(api: LibreNMSAPI, device_id: int) -> dict | None:
     """
     Detect if device is a stack/Virtual Chassis by analyzing ENTITY-MIB inventory.
     Vendor-agnostic using standard hierarchical structure.
@@ -166,16 +177,21 @@ def detect_virtual_chassis_from_inventory(api: LibreNMSAPI, device_id: int) -> d
             return None
 
         # Step 2: Find parent container index
-        # Could be class="stack" or the main "chassis"
+        # Prefer "stack" over "chassis" for deterministic VC detection
         parent_index = None
+        stack_index = None
+        chassis_index = None
         for item in root_items:
             item_class = item.get("entPhysicalClass")
-            if item_class in ["stack", "chassis"]:
-                parent_index = item.get("entPhysicalIndex")
-                logger.debug(f"VC detection: Found parent container at index {parent_index} for device {device_id}")
-                break
-
-        if not parent_index:
+            if item_class == "stack" and stack_index is None:
+                stack_index = item.get("entPhysicalIndex")
+            elif item_class == "chassis" and chassis_index is None:
+                chassis_index = item.get("entPhysicalIndex")
+        parent_index = stack_index if stack_index is not None else chassis_index
+        if parent_index is not None:
+            logger.debug(f"VC detection: Found parent container at index {parent_index} for device {device_id}")
+
+        if parent_index is None:
             return None
 
         # Step 3: Get children chassis at next level
@@ -200,11 +216,15 @@ def detect_virtual_chassis_from_inventory(api: LibreNMSAPI, device_id: int) -> d
         vc_name_pattern = _load_vc_member_name_pattern() if master_name else None
         members = []
         for idx, chassis in enumerate(chassis_items):
-            raw_position = chassis.get("entPhysicalParentRelPos", idx)
+            # entPhysicalParentRelPos is 1-based; fall back to idx+1 (not idx) so
+            # position 0 is never produced — VC positions must be ≥ 1.
+            raw_position = chassis.get("entPhysicalParentRelPos", idx + 1)
             try:
                 position = int(raw_position)
+                if position <= 0:
+                    position = idx + 1
             except (TypeError, ValueError):
-                position = idx
+                position = idx + 1
             member_data = {
                 "serial": chassis.get("entPhysicalSerialNum", ""),
                 "position": position,
@@ -214,13 +234,14 @@ def detect_virtual_chassis_from_inventory(api: LibreNMSAPI, device_id: int) -> d
                 "description": chassis.get("entPhysicalDescr", ""),
             }
 
-            # Generate suggested name if we have master name
+            # Generate suggested name if we have master name.
+            # position is already 1-based, so pass it directly (no +1).
             if master_name:
                 member_data["suggested_name"] = _generate_vc_member_name(
-                    master_name, position + 1, serial=member_data.get("serial"), pattern=vc_name_pattern
+                    master_name, position, serial=member_data.get("serial"), pattern=vc_name_pattern
                 )
             else:
-                member_data["suggested_name"] = f"Member-{position + 1}"
+                member_data["suggested_name"] = f"Member-{position}"
 
             members.append(member_data)
 
@@ -260,8 +281,9 @@ def _generate_vc_member_name(master_name: str, position: int, serial: str = None
         master_name: Name of the master/primary device
         position: VC position number
         serial: Optional serial number of the member device
-        pattern: Optional pre-loaded pattern; if None, loaded from settings via
-            _load_vc_member_name_pattern()
+        pattern: Optional pre-loaded name pattern; if None, loaded from settings.
+                 Pass a pre-loaded pattern when calling inside a loop to avoid
+                 repeated DB queries.
 
     Returns:
         Generated member device name
@@ -311,13 +333,16 @@ def update_vc_member_suggested_names(vc_data: dict, master_name: str) -> dict:
     # Load naming pattern once to avoid a DB query per member
     vc_pattern = _load_vc_member_name_pattern()
     for idx, member in enumerate(vc_data.get("members", [])):
-        raw_position = member.get("position", idx)
+        # Positions are stored as 1-based (from entPhysicalParentRelPos or idx+1 fallback).
+        # Use them directly for name generation; only replace 0/negative with 1-based fallback.
+        raw_position = member.get("position", idx + 1)
         try:
-            base_position = int(raw_position)
+            position = int(raw_position)
+            if position <= 0:
+                position = idx + 1
         except (TypeError, ValueError):
-            base_position = idx
-        position = base_position + 1  # Convert to 1-based position
-        member["position"] = base_position
+            position = idx + 1
+        member["position"] = position
         member["suggested_name"] = _generate_vc_member_name(
             master_name, position, serial=member.get("serial"), pattern=vc_pattern
         )
@@ -325,7 +350,23 @@ def update_vc_member_suggested_names(vc_data: dict, master_name: str) -> dict:
     return vc_data
 
 
-def create_virtual_chassis_with_members(master_device: Device, members_info: list, libre_device: dict):
+def _safe_pos(value) -> int | None:
+    """Return int position or None if not parseable."""
+    try:
+        return int(value)
+    except (TypeError, ValueError):
+        return None
+
+
+def _norm_serial(s) -> str:
+    """Normalize serial: strip whitespace; treat '-' as absent."""
+    s = str(s or "").strip()
+    return "" if s == "-" else s
+
+
+def create_virtual_chassis_with_members(
+    master_device: Device, members_info: list, libre_device: dict, server_key: str | None = None
+) -> VirtualChassis:
     """
     Create Virtual Chassis and member devices from detection info.
 
@@ -352,10 +393,18 @@ def create_virtual_chassis_with_members(master_device: Device, members_info: lis
         ]
     """
 
-    # Store original master device state for rollback
+    # original_master_name is still referenced in warning messages inside the atomic block.
     original_master_name = master_device.name
-    original_vc = master_device.virtual_chassis
-    original_vc_position = master_device.vc_position
+
+    # Find master's actual VC position from members_info by serial match; default to 1
+    _master_pos = 1
+    if _norm_serial(master_device.serial):
+        for _m in members_info:
+            if _norm_serial(_m.get("serial")) == _norm_serial(master_device.serial):
+                _found_pos = _safe_pos(_m.get("position"))
+                if _found_pos and _found_pos >= 1:
+                    _master_pos = _found_pos
+                break
 
     try:
         with transaction.atomic():
@@ -363,7 +412,7 @@ def create_virtual_chassis_with_members(master_device: Device, members_info: lis
             vc_pattern = _load_vc_member_name_pattern()
             # Rename master device to include position 1 pattern
             master_device_new_name = _generate_vc_member_name(
-                original_master_name, 1, serial=master_device.serial, pattern=vc_pattern
+                original_master_name, _master_pos, serial=master_device.serial, pattern=vc_pattern
             )
 
             # Check if renamed master conflicts with existing device
@@ -379,27 +428,44 @@ def create_virtual_chassis_with_members(master_device: Device, members_info: lis
 
             # Create VC using original base name
             vc_name = master_base_name
+            _device_id = libre_device.get("device_id") or master_device.pk
+            _domain_prefix = f"librenms-{server_key}" if server_key else "librenms"
             vc = VirtualChassis.objects.create(
                 name=vc_name,
                 master=master_device,
-                domain=f"librenms-{libre_device['device_id']}",
+                domain=f"{_domain_prefix}-{_device_id}",
             )
 
             # Update master device
             master_device.virtual_chassis = vc
-            master_device.vc_position = 1  # Master is position 1
+            master_device.vc_position = _master_pos
             master_device.save()
 
             # Create member devices for remaining positions
-            position = 2  # Start at 2 (master is 1)
+            position = _master_pos + 1  # Start after master position
+            used_positions = {_master_pos}  # Master occupies its actual position
             members_created = 0
 
             for member in members_info:
-                # Skip if this is the master's serial
-                if member.get("serial") == master_device.serial:
+                # Normalize serial and position up front so all skip-checks and
+                # downstream logic use consistent values (strips whitespace and
+                # treats the sentinel "-" as "no serial").
+                serial = str(member.get("serial") or "").strip()
+                if serial == "-":
+                    serial = ""
+                member_pos = _safe_pos(member.get("position"))
+
+                # Skip if this is the master's serial (only when both serials are non-empty)
+                if serial and serial == (master_device.serial or "").strip():
+                    continue
+                # Skip blank-serial entries that represent the master slot by position
+                if (
+                    not serial
+                    and member_pos is not None
+                    and master_device.vc_position is not None
+                    and member_pos == master_device.vc_position
+                ):
                     continue
-
-                serial = member.get("serial")
 
                 member_rack = master_device.rack
                 member_location = master_device.location or (
@@ -411,7 +477,25 @@ def create_virtual_chassis_with_members(master_device: Device, members_info: lis
                     logger.warning(f"Device with serial '{serial}' already exists, skipping VC member creation")
                     continue
 
-                member_name = _generate_vc_member_name(master_base_name, position, serial=serial, pattern=vc_pattern)
+                # Prefer the discovered SNMP position; fall back to sequential counter.
+                # member_pos was normalized via _safe_pos() above; 0 is not a valid vc_position.
+                discovered_pos = member_pos if (member_pos is not None and member_pos >= 1) else None
+                # If discovered_pos is already taken by another member, treat as absent.
+                if discovered_pos is not None and discovered_pos in used_positions:
+                    discovered_pos = None
+                # Consume next free sequential slot when no valid discovered_pos.
+                if discovered_pos is None:
+                    while position in used_positions:
+                        position += 1
+                    chosen_pos = position
+                    position += 1
+                else:
+                    chosen_pos = discovered_pos
+                    # Advance sequential counter past chosen position.
+                    position = max(position, chosen_pos + 1)
+                used_positions.add(chosen_pos)
+
+                member_name = _generate_vc_member_name(master_base_name, chosen_pos, serial=serial, pattern=vc_pattern)
 
                 # Check for duplicate name
                 if Device.objects.filter(name=member_name).exists():
@@ -428,15 +512,27 @@ def create_virtual_chassis_with_members(master_device: Device, members_info: lis
                     platform=master_device.platform,
                     serial=serial,
                     virtual_chassis=vc,
-                    vc_position=position,
+                    vc_position=chosen_pos,
                     comments=f"VC member (LibreNMS: {member.get('name', 'Unknown')})\n"
                     f"Auto-created from stack inventory",
                 )
                 members_created += 1
-                position += 1
 
             # Validate member count
-            expected_members = len([m for m in members_info if m.get("serial") != master_device.serial])
+            # Validate member count — exclude master-slot entries with blank serials
+            expected_members = len(
+                [
+                    m
+                    for m in members_info
+                    if not (_norm_serial(m.get("serial")) and _norm_serial(m.get("serial")) == master_device.serial)
+                    and not (
+                        not _norm_serial(m.get("serial"))
+                        and m.get("position") is not None
+                        and master_device.vc_position is not None
+                        and _safe_pos(m["position"]) == master_device.vc_position
+                    )
+                ]
+            )
             if members_created < expected_members:
                 logger.warning(
                     f"Created {members_created} members but expected {expected_members}. "
@@ -451,12 +547,10 @@ def create_virtual_chassis_with_members(master_device: Device, members_info: lis
             return vc
 
     except Exception as e:
-        # Rollback master device to original state
+        # The transaction.atomic() block above will roll back all DB changes automatically.
+        # Manual state restoration is redundant and the save() would fail in a broken transaction.
         logger.error(
-            f"Virtual Chassis creation failed for device {master_device.name}: {e}. Rolling back master device changes."
+            f"Virtual Chassis creation failed for device {master_device.name}: {e}",
+            exc_info=True,
         )
-        master_device.name = original_master_name
-        master_device.virtual_chassis = original_vc
-        master_device.vc_position = original_vc_position
-        master_device.save()
         raise
diff --git a/netbox_librenms_plugin/import_utils/vm_operations.py b/netbox_librenms_plugin/import_utils/vm_operations.py
index b75b69f7a9..0190c069ba 100644
--- a/netbox_librenms_plugin/import_utils/vm_operations.py
+++ b/netbox_librenms_plugin/import_utils/vm_operations.py
@@ -1,8 +1,9 @@
-"""Virtual machine import operations."""
+"""Virtual machine creation and import operations."""
 
 import logging
 
 from dcim.models import DeviceRole
+from django.db import transaction
 from django.utils import timezone
 from virtualization.models import Cluster
 
@@ -13,7 +14,13 @@
 logger = logging.getLogger(__name__)
 
 
-def create_vm_from_librenms(libre_device: dict, validation: dict, use_sysname: bool = True, role=None):
+def create_vm_from_librenms(
+    libre_device: dict,
+    validation: dict,
+    server_key: str,
+    use_sysname: bool = True,
+    strip_domain: bool = False,
+):
     """
     Create a NetBox VirtualMachine from LibreNMS device data.
 
@@ -21,7 +28,7 @@ def create_vm_from_librenms(libre_device: dict, validation: dict, use_sysname: b
         libre_device: Device data from LibreNMS
         validation: Validation result from validate_device_for_import with import_as_vm=True
         use_sysname: If True, prefer sysName; if False, use hostname
-        role: Optional DeviceRole to assign to the VM
+        server_key: LibreNMS server key used to store the librenms_id custom field
 
     Returns:
         Created VirtualMachine instance
@@ -37,14 +44,16 @@ def create_vm_from_librenms(libre_device: dict, validation: dict, use_sysname: b
     # Extract matched objects from validation
     cluster = validation["cluster"]["cluster"]
     platform = validation["platform"].get("platform")
+    role = validation.get("device_role", {}).get("role")
 
-    # Determine VM name - use pre-computed name if available (handles strip_domain)
-    vm_name = libre_device.get("_computed_name")
+    # Determine VM name - use pre-computed name if available (handles strip_domain),
+    # falling back to the validated resolved_name before recomputing from raw fields.
+    vm_name = libre_device.get("_computed_name") or validation.get("resolved_name")
     if not vm_name:
         vm_name = _determine_device_name(
             libre_device,
             use_sysname=use_sysname,
-            strip_domain=False,
+            strip_domain=strip_domain,
             device_id=libre_device.get("device_id"),
         )
 
@@ -58,15 +67,20 @@ def create_vm_from_librenms(libre_device: dict, validation: dict, use_sysname: b
         raise ValueError(f"device_id is a boolean ({raw_device_id!r}); expected an integer")
     librenms_device_id = int(raw_device_id)
 
-    # Create the VM with librenms_id custom field
-    vm = VirtualMachine.objects.create(
-        name=vm_name,
-        cluster=cluster,
-        role=role,  # Optional VM role
-        platform=platform,
-        comments=f"Imported from LibreNMS (device_id={librenms_device_id}) by netbox-librenms-plugin on {import_time}",
-        custom_field_data={"librenms_id": librenms_device_id},
-    )
+    from ..utils import set_librenms_device_id
+
+    # Create the VM and assign its LibreNMS ID atomically so a failure in
+    # set_librenms_device_id never leaves a VM without a mapping.
+    with transaction.atomic():
+        vm = VirtualMachine.objects.create(
+            name=vm_name,
+            cluster=cluster,
+            role=role,
+            platform=platform,
+            comments=f"Imported from LibreNMS (device_id={librenms_device_id}) by netbox-librenms-plugin on {import_time}",
+        )
+        set_librenms_device_id(vm, librenms_device_id, server_key)
+        vm.save()
 
     logger.info(f"Created VM {vm.name} (ID: {vm.pk}) from LibreNMS device {libre_device['device_id']}")
     return vm
@@ -136,15 +150,27 @@ def bulk_import_vms(
     log = job.logger if job else logger
 
     for idx, vm_id in enumerate(vm_ids, start=1):
-        # Check for job cancellation every 5 VMs
-        if job and idx % 5 == 0:
-            job.job.refresh_from_db()
-            job_status = job.job.status
-            status_value = job_status.value if hasattr(job_status, "value") else job_status
-            if status_value in ("failed", "errored"):
+        # Check for job cancellation before first VM and every 5 thereafter
+        if job and (idx == 1 or idx % 5 == 0):
+            cancelled = False
+            try:
+                from django_rq import get_queue
+                from rq.job import Job as RQJob
+
+                queue = get_queue("default")
+                rq_job = RQJob.fetch(str(job.job.job_id), connection=queue.connection)
+                if rq_job.is_failed or rq_job.is_stopped:
+                    cancelled = True
+            except Exception:
+                job.job.refresh_from_db()
+                job_status = job.job.status
+                status_value = job_status.value if hasattr(job_status, "value") else job_status
+                if status_value in ("failed", "errored", "stopped"):
+                    cancelled = True
+            if cancelled:
                 log.warning(f"Job cancelled at VM {idx} of {len(vm_ids)}")
                 break
-            log.info(f"Imported VM {idx} of {len(vm_ids)}")
+            log.info(f"Processing VM {idx} of {len(vm_ids)}")
 
         try:
             # Fetch device data (uses cache helper)
@@ -169,6 +195,7 @@ def bulk_import_vms(
                 api=api,
                 use_sysname=use_sysname_opt,
                 strip_domain=strip_domain_opt,
+                server_key=api.server_key,
             )
 
             # Check if VM already exists
@@ -191,21 +218,28 @@ def bulk_import_vms(
                 cluster = Cluster.objects.filter(id=cluster_id).first()
                 if cluster:
                     apply_cluster_to_validation(validation, cluster)
+                else:
+                    result["failed"].append(
+                        {"device_id": vm_id, "error": f"Selected cluster (id={cluster_id}) no longer exists"}
+                    )
+                    continue
 
             role = None
             if role_id:
                 role = DeviceRole.objects.filter(id=role_id).first()
                 if role:
                     apply_role_to_validation(validation, role, is_vm=True)
+                else:
+                    result["failed"].append(
+                        {"device_id": vm_id, "error": f"Selected role (id={role_id}) no longer exists"}
+                    )
+                    continue
 
             # Determine VM name
-            use_sysname = sync_options.get("use_sysname", True) if sync_options else True
-            strip_domain = sync_options.get("strip_domain", False) if sync_options else False
-
             vm_name = _determine_device_name(
                 libre_device,
-                use_sysname=use_sysname,
-                strip_domain=strip_domain,
+                use_sysname=use_sysname_opt,
+                strip_domain=strip_domain_opt,
                 device_id=vm_id,
             )
 
@@ -213,7 +247,13 @@ def bulk_import_vms(
             libre_device["_computed_name"] = vm_name
 
             # Create VM
-            vm = create_vm_from_librenms(libre_device, validation, use_sysname=use_sysname, role=role)
+            vm = create_vm_from_librenms(
+                libre_device,
+                validation,
+                use_sysname=use_sysname_opt,
+                strip_domain=strip_domain_opt,
+                server_key=api.server_key,
+            )
 
             result["success"].append(
                 {
diff --git a/netbox_librenms_plugin/jobs.py b/netbox_librenms_plugin/jobs.py
index f56d564e46..d8aa638c73 100644
--- a/netbox_librenms_plugin/jobs.py
+++ b/netbox_librenms_plugin/jobs.py
@@ -111,7 +111,7 @@ def run(
             "device_ids": device_ids,
             "total_processed": len(validated_devices),
             "filters": filters,
-            "server_key": server_key,
+            "server_key": api.server_key,
             "vc_detection_enabled": vc_detection_enabled,
             "use_sysname": use_sysname,
             "strip_domain": strip_domain,
@@ -166,6 +166,7 @@ def run(
         vm_imports,
         server_key=None,
         sync_options=None,
+        vc_detection_enabled=False,
         manual_mappings_per_device=None,
         libre_devices_cache=None,
         **kwargs,
@@ -178,6 +179,7 @@ def run(
             vm_imports: Dict mapping device_id to cluster/role info for VM imports
             server_key: Optional LibreNMS server key for multi-server setups
             sync_options: Dict with sync_interfaces, sync_cables, sync_ips, use_sysname, strip_domain
+            vc_detection_enabled: Whether VC detection was enabled during the filter step.
             manual_mappings_per_device: Dict mapping device_id to manual_mappings dict
             libre_devices_cache: Optional dict mapping device_id to pre-fetched device data
             **kwargs: Additional job parameters
@@ -208,10 +210,11 @@ def run(
             self.logger.info(f"Importing {len(device_ids)} devices...")
             device_result = bulk_import_devices_shared(
                 device_ids=device_ids,
-                server_key=server_key,
+                server_key=api.server_key,
                 sync_options=sync_options,
                 manual_mappings_per_device=manual_mappings_per_device,
                 libre_devices_cache=libre_devices_cache,
+                vc_detection_enabled=vc_detection_enabled,
                 job=self,  # Pass job context for logging and cancellation
                 user=self.job.user,  # Pass user for permission checks
             )
@@ -226,13 +229,25 @@ def run(
                 vm_imports, api, sync_options, libre_devices_cache, job=self, user=self.job.user
             )
 
-        # Combine results
-        imported_device_pks = [item["device"].pk for item in device_result.get("success", []) if item.get("device")]
-        imported_vm_pks = [item["device"].pk for item in vm_result.get("success", []) if item.get("device")]
+        # Combine results — partition device_result successes by model type since
+        # bulk_import_devices_shared() may return VirtualMachine objects when import_as_vm=True.
+        device_successes = []
+        vm_successes = list(vm_result.get("success", []))
+        for item in device_result.get("success", []):
+            obj = item.get("device")
+            if not obj:
+                continue
+            if obj._meta.model_name == "virtualmachine":
+                vm_successes.append(item)
+            else:
+                device_successes.append(item)
+
+        imported_device_pks = [item["device"].pk for item in device_successes]
+        imported_vm_pks = [item["device"].pk for item in vm_successes]
 
         # Also store LibreNMS device IDs for re-rendering table rows
-        imported_libre_device_ids = [item["device_id"] for item in device_result.get("success", [])]
-        imported_libre_vm_ids = [item["device_id"] for item in vm_result.get("success", [])]
+        imported_libre_device_ids = [item["device_id"] for item in device_successes]
+        imported_libre_vm_ids = [item["device_id"] for item in vm_successes]
 
         success_count = len(device_result.get("success", [])) + len(vm_result.get("success", []))
         failed_count = len(device_result.get("failed", [])) + len(vm_result.get("failed", []))
@@ -246,7 +261,7 @@ def run(
             "imported_vm_pks": imported_vm_pks,
             "imported_libre_device_ids": imported_libre_device_ids,
             "imported_libre_vm_ids": imported_libre_vm_ids,
-            "server_key": server_key,
+            "server_key": api.server_key,
             "total": total_count,
             "success_count": success_count,
             "failed_count": failed_count,
diff --git a/netbox_librenms_plugin/librenms_api.py b/netbox_librenms_plugin/librenms_api.py
index 811cc367d3..100b81a349 100644
--- a/netbox_librenms_plugin/librenms_api.py
+++ b/netbox_librenms_plugin/librenms_api.py
@@ -190,21 +190,16 @@ def get_librenms_id(self, obj):
             If found via API, stores ID in custom field if available,
             otherwise caches the value.
         """
-        librenms_id = obj.cf.get("librenms_id")
+        from netbox_librenms_plugin.utils import get_librenms_device_id
+
+        librenms_id = get_librenms_device_id(obj, self.server_key, auto_save=False)
         if librenms_id is not None:
-            if isinstance(librenms_id, str):
-                try:
-                    librenms_id = int(librenms_id)
-                    self._store_librenms_id(obj, librenms_id)
-                except (ValueError, TypeError):
-                    librenms_id = None  # empty or invalid string — fall through to discovery
-            if librenms_id is not None:
-                return librenms_id
+            return librenms_id
 
         # Check cache
         cache_key = self._get_cache_key(obj)
         librenms_id = cache.get(cache_key)
-        if librenms_id:
+        if librenms_id is not None:
             return librenms_id
 
         # Determine dynamically from API
@@ -215,23 +210,38 @@ def get_librenms_id(self, obj):
         # Try IP address
         if ip_address:
             librenms_id = self.get_device_id_by_ip(ip_address)
-            if librenms_id:
-                self._store_librenms_id(obj, librenms_id)
-                return librenms_id
+            if librenms_id is not None:
+                try:
+                    librenms_id = int(librenms_id)
+                except (ValueError, TypeError):
+                    librenms_id = None
+                if librenms_id is not None:
+                    self._store_librenms_id(obj, librenms_id)
+                    return librenms_id
 
         # Try primary IP's DNS name
         if dns_name:
             librenms_id = self.get_device_id_by_hostname(dns_name)
-            if librenms_id:
-                self._store_librenms_id(obj, librenms_id)
-                return librenms_id
+            if librenms_id is not None:
+                try:
+                    librenms_id = int(librenms_id)
+                except (ValueError, TypeError):
+                    librenms_id = None
+                if librenms_id is not None:
+                    self._store_librenms_id(obj, librenms_id)
+                    return librenms_id
 
         # Try hostname if FQDN
         if hostname:
             librenms_id = self.get_device_id_by_hostname(hostname)
-            if librenms_id:
-                self._store_librenms_id(obj, librenms_id)
-                return librenms_id
+            if librenms_id is not None:
+                try:
+                    librenms_id = int(librenms_id)
+                except (ValueError, TypeError):
+                    librenms_id = None
+                if librenms_id is not None:
+                    self._store_librenms_id(obj, librenms_id)
+                    return librenms_id
 
         return None
 
@@ -261,7 +271,9 @@ def _store_librenms_id(self, obj, librenms_id):
             None
         """
         if "librenms_id" in obj.cf:
-            obj.custom_field_data["librenms_id"] = librenms_id
+            from netbox_librenms_plugin.utils import set_librenms_device_id
+
+            set_librenms_device_id(obj, librenms_id, self.server_key)
             obj.save(update_fields=["custom_field_data"])
         else:
             # Use cache as fallback
@@ -288,7 +300,7 @@ def get_device_id_by_ip(self, ip_address):
             response.raise_for_status()
             device_data = response.json()["devices"][0]
             return device_data["device_id"]
-        except (requests.exceptions.RequestException, IndexError, KeyError):
+        except (requests.exceptions.RequestException, IndexError, KeyError, TypeError):
             return None
 
     def get_device_id_by_hostname(self, hostname):
@@ -311,7 +323,7 @@ def get_device_id_by_hostname(self, hostname):
             response.raise_for_status()
             device_data = response.json()["devices"][0]
             return device_data["device_id"]
-        except (requests.exceptions.RequestException, IndexError, KeyError):
+        except (requests.exceptions.RequestException, IndexError, KeyError, TypeError):
             return None
 
     def get_device_info(self, device_id):
@@ -336,7 +348,7 @@ def get_device_info(self, device_id):
                 device_data = response.json()["devices"][0]
                 return True, device_data
             return False, None
-        except requests.exceptions.RequestException:
+        except (requests.exceptions.RequestException, IndexError, KeyError, TypeError):
             return False, None
 
     def get_ports(self, device_id, with_vlans=True):
@@ -627,9 +639,12 @@ def get_device_ips(self, device_id):
                 verify=self.verify_ssl,
             )
             response.raise_for_status()
-            if response.status_code == 200:
-                ip_data = response.json()["addresses"]
-                return True, ip_data
+            data = response.json()
+            addresses = data.get("addresses") if isinstance(data, dict) else None
+            if not isinstance(addresses, list):
+                message = data.get("message") if isinstance(data, dict) else None
+                return False, message or "Unexpected response format: 'addresses' must be a list"
+            return True, addresses
         except requests.exceptions.RequestException as e:
             return False, str(e)
 
@@ -685,11 +700,13 @@ def get_device_inventory(self, device_id):
                 verify=self.verify_ssl,
             )
             response.raise_for_status()
-
-            if response.status_code == 200:
-                inventory_data = response.json()
-                return True, inventory_data.get("inventory", [])
-            return False, []
+            inventory_data = response.json()
+            inventory = inventory_data.get("inventory") if isinstance(inventory_data, dict) else None
+            if not isinstance(inventory, list):
+                msg = inventory_data.get("message", "") if isinstance(inventory_data, dict) else ""
+                logger.warning(f"Unexpected inventory response for device {device_id}: {inventory_data}")
+                return False, msg or "Unexpected response format: missing 'inventory' list"
+            return True, inventory
         except requests.exceptions.RequestException as e:
             return False, str(e)
 
@@ -717,12 +734,15 @@ def get_poller_groups(self):
                 verify=self.verify_ssl,
             )
             response.raise_for_status()
-
-            if response.status_code == 200:
-                result = response.json()
-                if result.get("status") == "ok":
-                    return True, result.get("get_poller_group", [])
-            return False, []
+            result = response.json()
+            if isinstance(result, dict) and result.get("status") == "ok":
+                poller_groups = result.get("get_poller_group")
+                if not isinstance(poller_groups, list):
+                    return False, result.get("message") or "Unexpected response format: missing 'get_poller_group' list"
+                return True, poller_groups
+            if isinstance(result, dict):
+                return False, result.get("message") or "Unexpected response format"
+            return False, "Unexpected response format: non-object JSON"
         except requests.exceptions.RequestException as e:
             return False, str(e)
 
@@ -767,15 +787,17 @@ def get_inventory_filtered(self, device_id, ent_physical_class=None, ent_physica
             )
             response.raise_for_status()
 
-            if response.status_code == 200:
-                data = response.json()
-                if data.get("status") == "ok":
-                    inventory = data.get("inventory", [])
-                    logger.debug(f"API returned {len(inventory)} items")
+            data = response.json()
+            if isinstance(data, dict) and data.get("status") == "ok":
+                inventory = data.get("inventory") if isinstance(data, dict) else None
+                if not isinstance(inventory, list):
+                    msg = data.get("message") if isinstance(data, dict) else None
+                    return False, msg or "Unexpected response format: missing 'inventory' list"
+                logger.debug(f"API returned {len(inventory)} items")
 
-                    # If we got results or didn't specify filters, return
-                    if inventory or not params:
-                        return True, inventory
+                # If we got results or didn't specify filters, return
+                if inventory or not params:
+                    return True, inventory
 
             # If filtered endpoint returned empty but we have filters,
             # try /all endpoint and filter client-side
@@ -784,7 +806,7 @@ def get_inventory_filtered(self, device_id, ent_physical_class=None, ent_physica
                 success, all_inventory = self.get_device_inventory(device_id)
 
                 if not success:
-                    return False, []
+                    return False, all_inventory
 
                 # Apply client-side filters
                 filtered = all_inventory
@@ -799,11 +821,13 @@ def get_inventory_filtered(self, device_id, ent_physical_class=None, ent_physica
 
                 return True, filtered
 
-            return False, []
+            return False, data.get("message", "Unexpected response format") if isinstance(
+                data, dict
+            ) else "Unexpected response format"
 
         except requests.exceptions.RequestException as e:
             logger.warning(f"Failed to fetch filtered inventory: {e}")
-            return False, []
+            return False, str(e)
 
     def list_devices(self, filters=None):
         """
@@ -863,12 +887,17 @@ def list_devices(self, filters=None):
                 verify=self.verify_ssl,
             )
             response.raise_for_status()
-            if response.status_code == 200:
-                result = response.json()
-                if result.get("status") == "ok":
-                    return True, result.get("devices", [])
-
-            return False, []
+            result = response.json()
+            if isinstance(result, dict) and result.get("status") == "ok":
+                devices = result.get("devices")
+                if not isinstance(devices, list):
+                    msg = result.get("message")
+                    return False, msg or "Unexpected response format: missing 'devices' list"
+                return True, devices
+
+            return False, result.get("message", "Unexpected response format") if isinstance(
+                result, dict
+            ) else "Unexpected response format"
         except requests.exceptions.RequestException as e:
             return False, str(e)
 
@@ -911,16 +940,20 @@ def get_device_vlans(self, device_id: int) -> tuple[bool, list | str]:
             )
             response.raise_for_status()
 
-            if response.status_code == 200:
-                result = response.json()
-                if result.get("status") == "ok":
-                    # Filter VLANs by device_id since resources endpoint returns all VLANs
-                    all_vlans = result.get("vlans", [])
-                    device_vlans = [v for v in all_vlans if str(v.get("device_id")) == str(device_id)]
-                    return True, device_vlans
+            result = response.json()
+            if isinstance(result, dict) and result.get("status") == "ok":
+                all_vlans = result.get("vlans") if isinstance(result, dict) else None
+                if not isinstance(all_vlans, list):
+                    msg = result.get("message") if isinstance(result, dict) else None
+                    return False, msg or "Unexpected response format: missing 'vlans' list"
+                # Filter VLANs by device_id since resources endpoint returns all VLANs
+                device_vlans = [
+                    v for v in all_vlans if isinstance(v, dict) and str(v.get("device_id")) == str(device_id)
+                ]
+                return True, device_vlans
+            if isinstance(result, dict):
                 return False, result.get("message", "Unexpected response format")
-
-            return False, f"HTTP {response.status_code}"
+            return False, "Unexpected response format"
         except requests.exceptions.HTTPError as e:
             if e.response.status_code == 404:
                 return False, "VLANs resource not found"
@@ -965,6 +998,8 @@ def get_port_vlan_details(self, port_id: int) -> tuple[bool, dict | str]:
 
             if response.status_code == 200:
                 result = response.json()
+                if not isinstance(result, dict):
+                    return False, "Unexpected response format"
                 port_data = result.get("port", [])
                 if port_data and len(port_data) > 0:
                     return True, port_data[0]
@@ -1019,7 +1054,15 @@ def parse_port_vlan_data(self, port_data: dict, interface_name_field: str = "ifN
         if vlans_data:
             # Parse from detailed vlans array
             for vlan_entry in vlans_data:
+                if not isinstance(vlan_entry, dict):
+                    continue
                 vlan_id = vlan_entry.get("vlan")
+                if vlan_id is None:
+                    continue
+                try:
+                    vlan_id = int(vlan_id)
+                except (ValueError, TypeError):
+                    continue
                 if vlan_entry.get("untagged") == 1:
                     untagged_vlan = vlan_id
                 else:
diff --git a/netbox_librenms_plugin/static/netbox_librenms_plugin/js/librenms_sync.js b/netbox_librenms_plugin/static/netbox_librenms_plugin/js/librenms_sync.js
index c56f9dee97..5b020bb366 100644
--- a/netbox_librenms_plugin/static/netbox_librenms_plugin/js/librenms_sync.js
+++ b/netbox_librenms_plugin/static/netbox_librenms_plugin/js/librenms_sync.js
@@ -544,74 +544,80 @@ function initializeVlanModalSave() {
             ? document.querySelectorAll('.vlan-edit-btn')
             : document.querySelectorAll(`.vlan-edit-btn[data-safe-name="${currentSafeName}"]`);
 
-        buttonsToUpdate.forEach(btn => {
-            try {
-                const btnVlans = JSON.parse(btn.dataset.vlans);
-                const groups = JSON.parse(btn.dataset.vlanGroups);
-                const btnSafeName = btn.dataset.safeName;
-                let changed = false;
-
-                btnVlans.forEach(v => {
-                    if (vidGroupMap.hasOwnProperty(String(v.vid))) {
-                        const newGroupId = vidGroupMap[String(v.vid)];
-                        v.group_id = newGroupId;
-                        if (v.missing) {
-                            v.group_name = 'Not in NetBox';
-                        } else {
-                            const matchedGroup = groups.find(g => String(g.id) === String(newGroupId));
-                            v.group_name = matchedGroup ? matchedGroup.name : '-- No Group (Global) --';
-                        }
+        // Apply DOM mutations (btn.dataset.vlans, hidden inputs, summary spans)
+        // Called only after a successful server response when persisting, or immediately otherwise.
+        function applyButtonUpdates() {
+            buttonsToUpdate.forEach(btn => {
+                try {
+                    const btnVlans = JSON.parse(btn.dataset.vlans);
+                    const groups = JSON.parse(btn.dataset.vlanGroups);
+                    const btnSafeName = btn.dataset.safeName;
+                    let changed = false;
+
+                    btnVlans.forEach(v => {
+                        if (vidGroupMap.hasOwnProperty(String(v.vid))) {
+                            const newGroupId = vidGroupMap[String(v.vid)];
+                            v.group_id = newGroupId;
+
+                            // Apply resolved missing/css state BEFORE computing group_name
+                            // so group_name reflects the verified state from the server.
+                            if (vidCssMap.hasOwnProperty(String(v.vid))) {
+                                v.css = vidCssMap[String(v.vid)];
+                                v.missing = vidMissingMap[String(v.vid)] || false;
+                            }
 
-                        // Apply resolved CSS from verify endpoint if available
-                        if (vidCssMap.hasOwnProperty(String(v.vid))) {
-                            v.css = vidCssMap[String(v.vid)];
-                            v.missing = vidMissingMap[String(v.vid)] || false;
-                        }
+                            if (v.missing) {
+                                v.group_name = 'Not in NetBox';
+                            } else {
+                                const matchedGroup = groups.find(g => String(g.id) === String(newGroupId));
+                                v.group_name = matchedGroup ? matchedGroup.name : '-- No Group (Global) --';
+                            }
 
-                        changed = true;
+                            changed = true;
 
-                        // Update the hidden input for this VID on this interface
-                        const input = document.querySelector(
-                            `input.vlan-group-hidden[name="vlan_group_${btnSafeName}_${v.vid}"]`
-                        );
-                        if (input) {
-                            input.value = newGroupId;
+                            // Update the hidden input for this VID on this interface
+                            const input = document.querySelector(
+                                `input.vlan-group-hidden[name="vlan_group_${btnSafeName}_${v.vid}"]`
+                            );
+                            if (input) {
+                                input.value = newGroupId;
+                            }
                         }
-                    }
-                });
+                    });
 
-                if (changed) {
-                    btn.dataset.vlans = JSON.stringify(btnVlans);
-                    // Update the tooltip and re-render inline summary colors
-                    const summarySpan = btn.previousElementSibling;
-                    if (summarySpan && summarySpan.tagName === 'SPAN') {
-                        const tooltipLines = btnVlans.map(v =>
-                            v.missing
-                                ? `VLAN ${v.vid}(${v.type}) \u2192 \u26A0 Not in NetBox`
-                                : `VLAN ${v.vid}(${v.type}) \u2192 ${v.group_name}`
-                        );
-                        summarySpan.title = tooltipLines.join('\n');
-
-                        // Re-render inline VLAN summary with correct colors
-                        const MAX_INLINE = 3;
-                        const inlineParts = btnVlans.slice(0, MAX_INLINE).map(v => {
-                            const warning = v.missing
-                                ? ' <i class="mdi mdi-alert text-danger" title="VLAN not in selected group\u2014use VLAN Sync first to create it"></i>'
-                                : '';
-                            return `<span class="${v.css}">${v.vid}(${v.type})${warning}</span>`;
-                        });
-                        let html = inlineParts.join(', ');
-                        if (btnVlans.length > MAX_INLINE) {
-                            const extra = btnVlans.length - MAX_INLINE;
-                            html += ` <span class="text-muted">+${extra} more</span>`;
+                    if (changed) {
+                        btn.dataset.vlans = JSON.stringify(btnVlans);
+                        // Update the tooltip and re-render inline summary colors
+                        const summarySpan = btn.previousElementSibling;
+                        if (summarySpan && summarySpan.tagName === 'SPAN') {
+                            const tooltipLines = btnVlans.map(v =>
+                                v.missing
+                                    ? `VLAN ${v.vid}(${v.type}) \u2192 \u26A0 Not in NetBox`
+                                    : `VLAN ${v.vid}(${v.type}) \u2192 ${v.group_name}`
+                            );
+                            summarySpan.title = tooltipLines.join('\n');
+
+                            // Re-render inline VLAN summary with correct colors
+                            const MAX_INLINE = 3;
+                            const inlineParts = btnVlans.slice(0, MAX_INLINE).map(v => {
+                                const warning = v.missing
+                                    ? ' <i class="mdi mdi-alert text-danger" title="VLAN not in selected group\u2014use VLAN Sync first to create it"></i>'
+                                    : '';
+                                return `<span class="${v.css}">${v.vid}(${v.type})${warning}</span>`;
+                            });
+                            let html = inlineParts.join(', ');
+                            if (btnVlans.length > MAX_INLINE) {
+                                const extra = btnVlans.length - MAX_INLINE;
+                                html += ` <span class="text-muted">+${extra} more</span>`;
+                            }
+                            summarySpan.innerHTML = html;
                         }
-                        summarySpan.innerHTML = html;
                     }
+                } catch (e) {
+                    // Skip buttons with invalid data
                 }
-            } catch (e) {
-                // Skip buttons with invalid data
-            }
-        });
+            });
+        }
 
         // Persist overrides in server cache so other table pages pick them up
         if (applyToAll && Object.keys(vidGroupMap).length > 0) {
@@ -624,7 +630,8 @@ function initializeVlanModalSave() {
                 },
                 body: JSON.stringify({
                     device_id: deviceId,
-                    vid_group_map: vidGroupMap
+                    vid_group_map: vidGroupMap,
+                    server_key: document.querySelector('input[name="server_key"]')?.value || null
                 })
             }).then(response => {
                 if (!response.ok) {
@@ -634,6 +641,8 @@ function initializeVlanModalSave() {
                         throw new Error(msg);
                     });
                 }
+                // Apply DOM mutations only after the server has persisted the overrides
+                applyButtonUpdates();
                 // Close modal only on success
                 const closeBtn = modalEl.querySelector('[data-bs-dismiss="modal"]');
                 if (closeBtn) {
@@ -650,7 +659,8 @@ function initializeVlanModalSave() {
                 alertEl.textContent = 'Failed to save VLAN group overrides: ' + error.message;
             });
         } else {
-            // No server persist needed — close immediately
+            // No server persist needed — apply DOM mutations and close immediately
+            applyButtonUpdates();
             const closeBtn = modalEl.querySelector('[data-bs-dismiss="modal"]');
             if (closeBtn) {
                 closeBtn.click();
@@ -774,7 +784,8 @@ function handleVRFChange(select, value) {
         body: JSON.stringify({
             device_id: deviceId,
             ip_address: fullIpAddress,  // Use full IP address with prefix
-            vrf_id: value
+            vrf_id: value,
+            server_key: document.querySelector('input[name="server_key"]')?.value || null
         })
     })
         .then(response => {
@@ -813,7 +824,8 @@ function handleInterfaceChange(select, value) {
         body: JSON.stringify({
             device_id: value,
             interface_name: select.dataset.interface,
-            interface_name_field: document.querySelector('input[name="interface_name_field"]:checked')?.value || null
+            interface_name_field: document.querySelector('input[name="interface_name_field"]:checked')?.value || null,
+            server_key: document.querySelector('input[name="server_key"]')?.value || null
         })
     })
         .then(response => {
@@ -859,7 +871,8 @@ function handleCableChange(select, value) {
         },
         body: JSON.stringify({
             device_id: value,
-            local_port_id: select.dataset.interface
+            local_port_id: select.dataset.interface,
+            server_key: document.querySelector('input[name="server_key"]')?.value || null
         })
     })
         .then(response => {
@@ -1434,6 +1447,156 @@ function initializeSyncFormSpinners() {
     });
 }
 
+
+/**
+ * Wire the "Install Selected" form to collect checked module-table rows before submit.
+ * The form is separate from the table (to avoid nested forms), so we copy the
+ * selected checkbox values into hidden inputs just before the form is submitted.
+ * Guard against duplicate listeners on repeated HTMX swaps via a data attribute.
+ */
+function handleInstallSelectedSubmit() {
+    // Remove any previously-injected hidden inputs to avoid duplicates
+    const form = document.getElementById('install-selected-form');
+    if (!form) return;
+    form.querySelectorAll('input[data-injected-select]').forEach(el => { el.remove(); });
+
+    const table = document.getElementById('librenms-module-table');
+    if (!table) return;
+
+    table.querySelectorAll('input[name="select"]:checked').forEach(cb => {
+        const hidden = document.createElement('input');
+        hidden.type = 'hidden';
+        hidden.name = 'select';
+        hidden.value = cb.value;
+        hidden.dataset.injectedSelect = '1';
+        form.appendChild(hidden);
+    });
+}
+
+function initializeInstallSelectedForm() {
+    const form = document.getElementById('install-selected-form');
+    if (!form) return;
+    if (form.dataset.installInit) return;
+    form.dataset.installInit = 'true';
+    form.addEventListener('submit', handleInstallSelectedSubmit);
+}
+
+/**
+ * Tracks the in-flight AbortController for the module replace preview fetch.
+ * Cancelled when a new Replace button is clicked before the previous fetch completes.
+ */
+let _activeReplaceController = null;
+
+/**
+ * Initialize Replace buttons on the module sync table.
+ * Each button carries module/ent_index/server_key as data attributes and opens
+ * the mismatch comparison modal by fetching the preview fragment from the server.
+ */
+function initializeModuleReplaceButtons() {
+    document.querySelectorAll('.module-replace-btn').forEach(btn => {
+        if (btn.dataset.replaceInitialized) return;
+        btn.dataset.replaceInitialized = 'true';
+
+        btn.addEventListener('click', function () {
+            // Cancel any in-flight preview request before starting a new one
+            if (_activeReplaceController) {
+                _activeReplaceController.abort();
+            }
+            _activeReplaceController = new AbortController();
+            const signal = _activeReplaceController.signal;
+
+            const previewUrl = this.dataset.previewUrl;
+            const moduleId = this.dataset.moduleId;
+            const entIndex = this.dataset.entIndex;
+            const serverKey = this.dataset.serverKey;
+
+            const params = new URLSearchParams({
+                module_id: moduleId,
+                ent_index: entIndex,
+                server_key: serverKey,
+            });
+
+            // Show shared HTMX modal with loading state
+            const modalContent = document.getElementById('htmx-modal-content');
+            if (modalContent) {
+                modalContent.innerHTML =
+                    '<div class="modal-header">' +
+                    '<h5 class="modal-title"><i class="mdi mdi-swap-horizontal me-1"></i>Module Mismatch</h5>' +
+                    '<button type="button" class="btn-close" onclick="closeHtmxModal()" aria-label="Close"></button>' +
+                    '</div>' +
+                    '<div class="modal-body text-center py-3" id="htmx-modal-body">' +
+                    '<i class="mdi mdi-loading mdi-spin mdi-36px"></i>' +
+                    '<p class="mt-2">Loading\u2026</p>' +
+                    '</div>';
+            }
+
+            // Show modal using direct class manipulation (consistent with openBulkVCModal)
+            const htmxModal = document.getElementById('htmx-modal');
+            if (htmxModal) {
+                htmxModal.classList.add('show');
+                htmxModal.style.display = 'block';
+                htmxModal.setAttribute('aria-modal', 'true');
+                htmxModal.removeAttribute('aria-hidden');
+                let backdrop = document.querySelector('.modal-backdrop');
+                if (!backdrop) {
+                    backdrop = document.createElement('div');
+                    backdrop.className = 'modal-backdrop fade show';
+                    document.body.appendChild(backdrop);
+                }
+                document.body.classList.add('modal-open');
+            }
+
+            // Fetch preview content and inject into modal body
+            fetch(`${previewUrl}?${params.toString()}`, {
+                signal,
+                headers: { 'X-CSRFToken': document.querySelector('[name=csrfmiddlewaretoken]').value },
+            })
+                .then(response => {
+                    if (!response.ok) return response.text().then(t => { throw new Error(t); });
+                    return response.text();
+                })
+                .then(html => {
+                    const modalBody = document.getElementById('htmx-modal-body');
+                    if (modalBody) {
+                        modalBody.innerHTML = html;
+                    }
+                })
+                .catch(err => {
+                    if (err.name === 'AbortError') return; // Superseded by a newer click — ignore
+                    const modalBody = document.getElementById('htmx-modal-body');
+                    if (modalBody) {
+                        const alert = document.createElement('div');
+                        alert.className = 'alert alert-danger';
+                        const icon = document.createElement('i');
+                        icon.className = 'mdi mdi-alert me-1';
+                        alert.appendChild(icon);
+                        alert.appendChild(document.createTextNode(err.message || 'Failed to load preview.'));
+                        modalBody.textContent = '';
+                        modalBody.appendChild(alert);
+                    }
+                });
+        });
+    });
+}
+
+function closeHtmxModal() {
+    // Abort any in-flight module-replace preview request
+    if (typeof _activeReplaceController !== 'undefined' && _activeReplaceController) {
+        _activeReplaceController.abort();
+        _activeReplaceController = null;
+    }
+    const htmxModal = document.getElementById('htmx-modal');
+    if (htmxModal) {
+        htmxModal.classList.remove('show');
+        htmxModal.style.display = 'none';
+        htmxModal.setAttribute('aria-hidden', 'true');
+        htmxModal.removeAttribute('aria-modal');
+        const backdrop = document.querySelector('.modal-backdrop');
+        if (backdrop) backdrop.remove();
+        document.body.classList.remove('modal-open');
+    }
+}
+
 // ============================================
 // INITIALIZATION
 // ============================================
@@ -1458,6 +1621,8 @@ function initializeScripts() {
     initializeNetBoxOnlyInterfaces();
     initializeSyncFormSpinners();
     initializeVlanSyncGroupSelects();
+    initializeInstallSelectedForm();
+    initializeModuleReplaceButtons();
 }
 
 
diff --git a/netbox_librenms_plugin/tables/device_status.py b/netbox_librenms_plugin/tables/device_status.py
index da5b02d0bf..995a623ec4 100644
--- a/netbox_librenms_plugin/tables/device_status.py
+++ b/netbox_librenms_plugin/tables/device_status.py
@@ -471,12 +471,12 @@ def render_actions(self, value, record):
                 btn_class = "btn-outline-danger"
                 btn_icon = "mdi-alert-circle"
                 btn_label = " Conflict"
-                btn_title = "Resolve conflict"
+                btn_title = "View conflict details"
             elif has_actions:
                 btn_class = "btn-outline-warning"
                 btn_icon = "mdi-alert"
                 btn_label = " Conflict"
-                btn_title = "Resolve conflict"
+                btn_title = "View conflict details"
             elif has_name_sync or has_sync_needed:
                 btn_class = "btn-outline-warning"
                 btn_icon = "mdi-information-outline"
@@ -486,7 +486,7 @@ def render_actions(self, value, record):
                 btn_class = "btn-outline-warning"
                 btn_icon = "mdi-database-alert"
                 btn_label = " Legacy ID"
-                btn_title = "Migrate Legacy ID"
+                btn_title = "View legacy ID migration details"
             else:
                 btn_class = "btn-outline-success"
                 btn_icon = "mdi-check-circle"
diff --git a/netbox_librenms_plugin/tables/interfaces.py b/netbox_librenms_plugin/tables/interfaces.py
index 5ceb30bf51..1216313da4 100644
--- a/netbox_librenms_plugin/tables/interfaces.py
+++ b/netbox_librenms_plugin/tables/interfaces.py
@@ -13,6 +13,7 @@
     convert_speed_to_kbps,
     format_mac_address,
     get_interface_name_field,
+    get_librenms_device_id,
     get_missing_vlan_warning,
     get_table_paginate_count,
     get_tagged_vlan_css_class,
@@ -46,11 +47,12 @@ class Meta:
             "id": "librenms-interface-table",
         }
 
-    def __init__(self, *args, device=None, interface_name_field=None, vlan_groups=None, **kwargs):
+    def __init__(self, *args, device=None, interface_name_field=None, vlan_groups=None, server_key="default", **kwargs):
         """Initialize table with device context and interface name field."""
         self.device = device
         self.interface_name_field = interface_name_field or get_interface_name_field()
         self.vlan_groups = vlan_groups or []
+        self.server_key = server_key
 
         # Update column accessors after initialization
         for column in ["selection", "name"]:
@@ -149,7 +151,7 @@ def render_vlans(self, value, record):
             all_vlans.append(("T", vid))
 
         if not all_vlans:
-            return format_html("—")
+            return mark_safe("—")
 
         interface_name = record.get(self.interface_name_field, "")
         safe_name = interface_name.replace("/", "_").replace(":", "_")
@@ -360,7 +362,7 @@ def render_librenms_id(self, value, record):
         if not netbox_interface:
             return mark_safe(f'<span class="text-danger">{value}</span>')
 
-        netbox_librenms_id = netbox_interface.custom_field_data.get("librenms_id")
+        netbox_librenms_id = get_librenms_device_id(netbox_interface, self.server_key, auto_save=False)
 
         if netbox_librenms_id is None:
             return mark_safe(
@@ -467,7 +469,7 @@ def render_mapping_tooltip(self, value, speed, mapping):
             )
         else:
             display = value
-            icon = format_html('<i class="mdi mdi-link-variant-off" title="No mapping to NetBox type"></i>')
+            icon = mark_safe('<i class="mdi mdi-link-variant-off" title="No mapping to NetBox type"></i>')
         return display, icon
 
     def format_interface_data(self, port_data, device):
diff --git a/netbox_librenms_plugin/tables/ipaddresses.py b/netbox_librenms_plugin/tables/ipaddresses.py
index c076d54ba8..8c9e1bfe21 100644
--- a/netbox_librenms_plugin/tables/ipaddresses.py
+++ b/netbox_librenms_plugin/tables/ipaddresses.py
@@ -1,5 +1,5 @@
 import django_tables2 as tables
-from django.utils.html import format_html
+from django.utils.html import format_html, mark_safe
 from netbox.tables.columns import ToggleColumn
 from utilities.paginator import EnhancedPaginator
 
@@ -91,14 +91,14 @@ def render_status(self, value, record):
                 record["ip_address"],
             )
         elif value == "matched":
-            return format_html('<span class="text-success"><i class="mdi mdi-check-circle"></i> Synced</span>')
+            return mark_safe('<span class="text-success"><i class="mdi mdi-check-circle"></i> Synced</span>')
         elif record.get("interface_url"):
             return format_html(
                 '<button type="submit" class="btn btn-sm btn-primary" onclick="document.getElementById(\'selected_ip\').value=\'{}\'">'
                 '<i class="mdi mdi-plus-thick" aria-hidden="true"></i> Create</button>',
                 record["ip_address"],
             )
-        return format_html('<span class="text-muted">Missing NetBox Object</span>')
+        return mark_safe('<span class="text-muted">Missing NetBox Object</span>')
 
     def render_device(self, value, record):
         """Render the device column with a link if available"""
diff --git a/netbox_librenms_plugin/tables/vlans.py b/netbox_librenms_plugin/tables/vlans.py
index 75c2f5e771..1b078b87b9 100644
--- a/netbox_librenms_plugin/tables/vlans.py
+++ b/netbox_librenms_plugin/tables/vlans.py
@@ -1,5 +1,5 @@
 import django_tables2 as tables
-from django.utils.html import format_html
+from django.utils.html import format_html, format_html_join
 from django.utils.safestring import mark_safe
 from netbox.tables.columns import ToggleColumn
 from utilities.paginator import EnhancedPaginator
@@ -124,12 +124,30 @@ def render_vlan_group_selection(self, value, record):
             # Priority 2: unique VID match
             selected_group_id = record["auto_selected_group_id"]
 
-        # Build the select element
-        options = ['<option value="">-- No Group (Global) --</option>']
-        for group in self.vlan_groups:
-            selected = "selected" if group.pk == selected_group_id else ""
-            scope_info = f" ({group.scope})" if group.scope else ""
-            options.append(f'<option value="{group.pk}" {selected}>{group.name}{scope_info}</option>')
+        # Build the select element using format_html_join to prevent XSS
+        options_html = format_html_join(
+            "",
+            '<option value="{}" data-scope="{}"{}>{}{}</option>',
+            [
+                (
+                    "",
+                    "",
+                    "",
+                    "-- No Group (Global) --",
+                    "",
+                ),
+            ]
+            + [
+                (
+                    group.pk,
+                    group.scope_id if group.scope_id else "",
+                    " selected" if group.pk == selected_group_id else "",
+                    group.name,
+                    f" ({group.scope})" if group.scope else "",
+                )
+                for group in self.vlan_groups
+            ],
+        )
 
         select_html = format_html(
             '<select name="vlan_group_{}" class="form-select form-select-sm vlan-sync-group-select"'
@@ -137,12 +155,12 @@ def render_vlan_group_selection(self, value, record):
             vlan_id,
             vlan_id,
             record.get("name", ""),
-            mark_safe("".join(options)),
+            options_html,
         )
 
         # Add warning icon if ambiguous (VID exists in multiple groups at same priority level)
         if record.get("is_ambiguous") and not record.get("exists_in_netbox"):
-            warning_html = format_html(
+            warning_html = mark_safe(
                 '<i class="mdi mdi-alert text-warning ms-1" '
                 'title="VID exists in multiple groups at the same scope level. Please select the target group."></i>'
             )
@@ -153,8 +171,8 @@ def render_vlan_group_selection(self, value, record):
     def render_state(self, value, record):
         """Render VLAN state (active/inactive)."""
         if value == LIBRENMS_VLAN_STATE_ACTIVE or value == "active":
-            return format_html('<span class="text-success">Active</span>')
-        return format_html('<span class="text-muted">Inactive</span>')
+            return mark_safe('<span class="text-success">Active</span>')
+        return mark_safe('<span class="text-muted">Inactive</span>')
 
     def configure(self, request):
         """Configure the table with pagination."""
diff --git a/netbox_librenms_plugin/templates/netbox_librenms_plugin/_cable_sync_content.html b/netbox_librenms_plugin/templates/netbox_librenms_plugin/_cable_sync_content.html
index c42534a73d..485676360e 100644
--- a/netbox_librenms_plugin/templates/netbox_librenms_plugin/_cable_sync_content.html
+++ b/netbox_librenms_plugin/templates/netbox_librenms_plugin/_cable_sync_content.html
@@ -5,6 +5,7 @@
 {% if cable_sync.table %}
 <form method="post" action="{% url 'plugins:netbox_librenms_plugin:sync_device_cables' cable_sync.object.pk %}">
     {% csrf_token %}
+    {% if cable_sync.server_key %}<input type="hidden" name="server_key" value="{{ cable_sync.server_key }}">{% endif %}
     <input type="hidden" id="selected_port" name="select" value="">
     <div class="noprint d-flex justify-content-between align-items-center mt-3 mb-3">
         <div>
diff --git a/netbox_librenms_plugin/templates/netbox_librenms_plugin/_interface_sync_content.html b/netbox_librenms_plugin/templates/netbox_librenms_plugin/_interface_sync_content.html
index 3d7e1406cd..c8a51bdcad 100644
--- a/netbox_librenms_plugin/templates/netbox_librenms_plugin/_interface_sync_content.html
+++ b/netbox_librenms_plugin/templates/netbox_librenms_plugin/_interface_sync_content.html
@@ -9,6 +9,7 @@
     action="{% url 'plugins:netbox_librenms_plugin:sync_selected_interfaces' object_type=model_name object_id=interface_sync.object.pk %}?interface_name_field={{ interface_name_field }}">
     {% endwith %}
     {% csrf_token %}
+    {% if interface_sync.server_key %}<input type="hidden" name="server_key" value="{{ interface_sync.server_key }}">{% endif %}
     {% block table_actions %}
     <div class="noprint d-flex justify-content-between align-items-center mt-3 mb-3">
         <div>
diff --git a/netbox_librenms_plugin/templates/netbox_librenms_plugin/_ipaddress_sync_content.html b/netbox_librenms_plugin/templates/netbox_librenms_plugin/_ipaddress_sync_content.html
index a31114de1f..e73bb83961 100644
--- a/netbox_librenms_plugin/templates/netbox_librenms_plugin/_ipaddress_sync_content.html
+++ b/netbox_librenms_plugin/templates/netbox_librenms_plugin/_ipaddress_sync_content.html
@@ -7,6 +7,7 @@
 <form method="post" action="{% url 'plugins:netbox_librenms_plugin:sync_device_ip_addresses' object_type=model_name pk=ip_sync.object.pk %}">
 {% endwith %}
     {% csrf_token %}
+    {% if ip_sync.server_key %}<input type="hidden" name="server_key" value="{{ ip_sync.server_key }}">{% endif %}
     <input type="hidden" id="selected_ip" name="select" value="">
     <div class="noprint d-flex justify-content-between align-items-center mt-3 mb-3">
         <div>
diff --git a/netbox_librenms_plugin/templates/netbox_librenms_plugin/_vlan_sync_content.html b/netbox_librenms_plugin/templates/netbox_librenms_plugin/_vlan_sync_content.html
index 017f888ec1..8221f29e38 100644
--- a/netbox_librenms_plugin/templates/netbox_librenms_plugin/_vlan_sync_content.html
+++ b/netbox_librenms_plugin/templates/netbox_librenms_plugin/_vlan_sync_content.html
@@ -21,6 +21,7 @@
       action="{% url 'plugins:netbox_librenms_plugin:sync_selected_vlans' object_type=model_name object_id=vlan_sync.object.pk %}">
 {% endwith %}
     {% csrf_token %}
+    {% if vlan_sync.server_key %}<input type="hidden" name="server_key" value="{{ vlan_sync.server_key }}">{% endif %}
     <input type="hidden" name="action" value="create_vlans">
 
     <div class="noprint d-flex justify-content-between align-items-center mt-3 mb-3">
diff --git a/netbox_librenms_plugin/templates/netbox_librenms_plugin/htmx/device_validation_details.html b/netbox_librenms_plugin/templates/netbox_librenms_plugin/htmx/device_validation_details.html
index 8141c846d0..ba460b6bb0 100644
--- a/netbox_librenms_plugin/templates/netbox_librenms_plugin/htmx/device_validation_details.html
+++ b/netbox_librenms_plugin/templates/netbox_librenms_plugin/htmx/device_validation_details.html
@@ -27,7 +27,7 @@ <h5 class="modal-title">
 
   {# Compute existing device URL once for use throughout #}
   {% if validation.existing_device %}
-    {% if validation.import_as_vm or validation.existing_device.cluster %}
+    {% if existing_device_model_name == "virtualmachine" %}
       {% url 'virtualization:virtualmachine' pk=validation.existing_device.pk as existing_device_url %}
     {% else %}
       {% url 'dcim:device' pk=validation.existing_device.pk as existing_device_url %}
@@ -112,13 +112,14 @@ <h6 class="card-header d-flex justify-content-between align-items-center">
                     <a href="{{ existing_device_url }}" target="_blank" rel="noopener noreferrer">
                       {{ validation.existing_device.name }}
                     </a>
-                    {% if validation.name_sync_available and existing_device_model_name != "virtualmachine" %}
+                    {% if validation.name_sync_available %}
                       <form style="display:inline" class="ms-2"
                             hx-post="{% url 'plugins:netbox_librenms_plugin:device_conflict_action' device_id=libre_device.device_id %}"
                             hx-swap="none"
                             hx-include="#use-sysname-toggle, #strip-domain-toggle">
                         {% csrf_token %}
                         <input type="hidden" name="existing_device_id" value="{{ validation.existing_device.pk }}">
+                        <input type="hidden" name="existing_device_type" value="{{ existing_device_model_name|default:'device' }}">
                         <input type="hidden" name="action" value="sync_name">
                         <button type="submit" class="btn btn-sm btn-outline-primary py-0 px-1" title="Sync name to {{ validation.suggested_name }}" aria-label="Sync name to {{ validation.suggested_name }}">
                           <i class="mdi mdi-sync"></i>
@@ -132,7 +133,7 @@ <h6 class="card-header d-flex justify-content-between align-items-center">
                 <td>{{ validation.resolved_name|default:libre_device.sysName|default:libre_device.hostname }}</td>
               </tr>
 
-              {% if not validation.import_as_vm %}
+              {% if not validation.existing_device and not validation.import_as_vm or validation.existing_device and existing_device_model_name != "virtualmachine" %}
               {# Site row #}
               <tr>
                 <td style="padding-left: 0.75rem;">Site</td>
@@ -167,6 +168,7 @@ <h6 class="card-header d-flex justify-content-between align-items-center">
                           hx-include="#use-sysname-toggle, #strip-domain-toggle">
                       {% csrf_token %}
                       <input type="hidden" name="existing_device_id" value="{{ validation.existing_device.pk }}">
+                      <input type="hidden" name="existing_device_type" value="{{ existing_device_model_name|default:'device' }}">
                       <input type="hidden" name="action" value="update_type">
                       <input type="hidden" name="force" value="on">
                       <button type="submit" class="btn btn-sm btn-outline-danger py-0 px-1" title="Update to LibreNMS type" aria-label="Update to LibreNMS type">
@@ -181,6 +183,7 @@ <h6 class="card-header d-flex justify-content-between align-items-center">
                             hx-swap="none">
                         {% csrf_token %}
                         <input type="hidden" name="existing_device_id" value="{{ validation.existing_device.pk }}">
+                        <input type="hidden" name="existing_device_type" value="{{ existing_device_model_name|default:'device' }}">
                         <input type="hidden" name="action" value="sync_device_type">
                         <button type="submit" class="btn btn-sm btn-outline-primary py-0 px-1" title="Sync device type" aria-label="Sync device type">
                           <i class="mdi mdi-sync"></i>
@@ -203,7 +206,7 @@ <h6 class="card-header d-flex justify-content-between align-items-center">
               {% endif %}
 
               {# Serial row (only for devices) #}
-              {% if not validation.import_as_vm %}
+              {% if not validation.existing_device and not validation.import_as_vm or validation.existing_device and existing_device_model_name != "virtualmachine" %}
               <tr>
                 <td style="padding-left: 0.75rem;">Serial</td>
                 <td>
@@ -224,6 +227,7 @@ <h6 class="card-header d-flex justify-content-between align-items-center">
                             hx-swap="none">
                         {% csrf_token %}
                         <input type="hidden" name="existing_device_id" value="{{ validation.existing_device.pk }}">
+                        <input type="hidden" name="existing_device_type" value="{{ existing_device_model_name|default:'device' }}">
                         <input type="hidden" name="action" value="sync_serial">
                         <button type="submit" class="btn btn-sm btn-outline-primary py-0 px-1" title="Sync serial from LibreNMS" aria-label="Sync serial from LibreNMS">
                           <i class="mdi mdi-sync"></i>
@@ -279,6 +283,7 @@ <h6 class="card-header d-flex justify-content-between align-items-center">
                               hx-swap="none">
                           {% csrf_token %}
                           <input type="hidden" name="existing_device_id" value="{{ validation.existing_device.pk }}">
+                          <input type="hidden" name="existing_device_type" value="{{ existing_device_model_name|default:'device' }}">
                           <input type="hidden" name="action" value="sync_platform">
                           <button type="submit" class="btn btn-sm btn-outline-primary py-0 px-1" title="Sync platform" aria-label="Sync platform">
                             <i class="mdi mdi-sync"></i>
@@ -304,6 +309,7 @@ <h6 class="card-header d-flex justify-content-between align-items-center">
                           hx-swap="none">
                       {% csrf_token %}
                       <input type="hidden" name="existing_device_id" value="{{ validation.existing_device.pk }}">
+                      <input type="hidden" name="existing_device_type" value="{{ existing_device_model_name|default:'device' }}">
                       <input type="hidden" name="action" value="sync_platform">
                       <button type="submit" class="btn btn-sm btn-outline-primary py-0 px-1" title="Sync platform" aria-label="Sync platform">
                         <i class="mdi mdi-sync"></i>
@@ -317,7 +323,7 @@ <h6 class="card-header d-flex justify-content-between align-items-center">
                 <td>{{ libre_device.os|default:"—" }}</td>
               </tr>
 
-              {% if validation.import_as_vm %}
+              {% if validation.import_as_vm and not validation.existing_device or validation.existing_device and existing_device_model_name == "virtualmachine" %}
               {# Cluster row (VMs only) #}
               <tr>
                 <td style="padding-left: 0.75rem;">Cluster</td>
@@ -376,7 +382,13 @@ <h6 class="card-header d-flex justify-content-between align-items-center">
   {% if validation.existing_device %}
     {% if validation.existing_match_type == 'librenms_id' %}
       <div class="alert alert-info py-2 mb-3 d-flex flex-wrap align-items-center gap-1">
-        <span class="badge bg-info-lt me-1"><i class="mdi mdi-check-decagram"></i> Linked — ID {{ libre_device.device_id }}</span>
+        {% if existing_id_servers %}
+          {% for srv in existing_id_servers %}
+            <span class="badge bg-info-lt me-1"><i class="mdi mdi-check-decagram"></i> Linked — ID {{ srv.device_id }} @ {{ srv.display_name }}</span>
+          {% endfor %}
+        {% else %}
+          <span class="badge bg-info-lt me-1"><i class="mdi mdi-check-decagram"></i> Linked — ID {{ libre_device.device_id }}</span>
+        {% endif %}
         {% if validation.name_matches %}
           <span class="badge bg-success-lt me-1"><i class="mdi mdi-check-circle-outline"></i> Name match</span>
         {% elif validation.name_sync_available %}
@@ -392,7 +404,38 @@ <h6 class="card-header d-flex justify-content-between align-items-center">
         {% if validation.device_type_mismatch %}
           <span class="badge bg-danger-lt me-1"><i class="mdi mdi-alert-circle"></i> Type mismatch</span>
         {% endif %}
+        {% if validation.librenms_id_needs_migration %}
+          <span class="badge bg-warning-lt me-1"><i class="mdi mdi-database-alert"></i> Legacy ID format</span>
+        {% endif %}
       </div>
+      {% if validation.librenms_id_needs_migration %}
+      <div class="mb-3">
+        <form style="display:inline"
+              hx-post="{% url 'plugins:netbox_librenms_plugin:device_conflict_action' device_id=libre_device.device_id %}"
+              hx-swap="none">
+          {% csrf_token %}
+          <input type="hidden" name="existing_device_id" value="{{ validation.existing_device.pk }}">
+          <input type="hidden" name="existing_device_type" value="{{ existing_device_model_name|default:'device' }}">
+          <input type="hidden" name="server_key" value="{{ server_key }}">
+          <input type="hidden" name="action" value="migrate_librenms_id">
+          {% if validation.existing_device.cluster %}
+          <input type="hidden" name="cluster_{{ libre_device.device_id }}" value="{{ validation.existing_device.cluster.pk }}">
+          {% endif %}
+          {% if not validation.serial_confirmed %}
+            <div class="form-check mb-2">
+              <input class="form-check-input" type="checkbox" name="force" id="force-migrate-{{ libre_device.device_id }}"
+                     onchange="this.closest('form').querySelector('.migrate-btn').disabled = !this.checked">
+              <label class="form-check-label text-warning" for="force-migrate-{{ libre_device.device_id }}">
+                <i class="mdi mdi-alert"></i> Serial not confirmed — check to migrate anyway
+              </label>
+            </div>
+          {% endif %}
+          <button type="submit" class="btn btn-sm btn-warning migrate-btn"{% if not validation.serial_confirmed %} disabled{% endif %}>
+            <i class="mdi mdi-database-sync"></i> Migrate ID format
+          </button>
+        </form>
+      </div>
+      {% endif %}
 
     {% elif validation.existing_match_type == 'hostname' %}
       <div class="alert alert-warning py-2 mb-3 d-flex flex-wrap align-items-center gap-1">
@@ -432,6 +475,7 @@ <h6 class="card-header d-flex justify-content-between align-items-center">
               hx-include="#use-sysname-toggle, #strip-domain-toggle">
           {% csrf_token %}
           <input type="hidden" name="existing_device_id" value="{{ validation.existing_device.pk }}">
+          <input type="hidden" name="existing_device_type" value="{{ existing_device_model_name|default:'device' }}">
           {% if validation.device_type_mismatch %}
             <div class="form-check mb-2">
               <input class="form-check-input" type="checkbox" name="force" id="force-hostname-{{ libre_device.device_id }}"
@@ -480,6 +524,7 @@ <h6 class="card-header d-flex justify-content-between align-items-center">
               hx-include="#use-sysname-toggle, #strip-domain-toggle">
           {% csrf_token %}
           <input type="hidden" name="existing_device_id" value="{{ validation.existing_device.pk }}">
+          <input type="hidden" name="existing_device_type" value="{{ existing_device_model_name|default:'device' }}">
           {% if validation.device_type_mismatch %}
             <div class="form-check mb-2">
               <input class="form-check-input" type="checkbox" name="force" id="force-serial-{{ libre_device.device_id }}"
@@ -557,7 +602,7 @@ <h6 class="card-header d-flex justify-content-between align-items-center">
 
 <div class="modal-footer">
   {% if validation.existing_device %}
-    {% if validation.import_as_vm or validation.existing_device.cluster %}
+    {% if existing_device_model_name == "virtualmachine" %}
       <a href="{{ existing_device_url }}"
          class="btn btn-primary btn-sm" target="_blank" rel="noopener noreferrer">
         <i class="mdi mdi-open-in-new"></i> View VM in NetBox
diff --git a/netbox_librenms_plugin/templates/netbox_librenms_plugin/librenms_sync_base.html b/netbox_librenms_plugin/templates/netbox_librenms_plugin/librenms_sync_base.html
index 82fd96ff03..d326e0f697 100644
--- a/netbox_librenms_plugin/templates/netbox_librenms_plugin/librenms_sync_base.html
+++ b/netbox_librenms_plugin/templates/netbox_librenms_plugin/librenms_sync_base.html
@@ -29,7 +29,72 @@
 {% block content %}
 
 <!-- LibreNMS Server Information -->
-{% if librenms_server_info %}
+{% if all_server_mappings %}
+<div class="card mb-3">
+    <div class="card-header d-flex justify-content-between align-items-center py-2">
+        <span><i class="mdi mdi-server-network text-primary me-1"></i><strong>LibreNMS Connections</strong></span>
+        {% if librenms_server_info and not librenms_server_info.is_legacy %}
+        <a href="{% url 'plugins:netbox_librenms_plugin:settings' %}" class="btn btn-sm btn-outline-primary">
+            <i class="mdi mdi-cog"></i> Change Server
+        </a>
+        {% endif %}
+    </div>
+    <div class="card-body p-0">
+        <table class="table table-sm mb-0">
+            <tbody>
+            {% for mapping in all_server_mappings %}
+            <tr>
+                <td class="ps-3" style="width:40%">
+                    {% if mapping.is_active %}
+                    <i class="mdi mdi-check-circle text-success me-1" title="Currently active server"></i>
+                    {% elif mapping.is_configured %}
+                    <i class="mdi mdi-server-network text-muted me-1"></i>
+                    {% else %}
+                    <i class="mdi mdi-server-off text-danger me-1" title="Server not configured in NetBox"></i>
+                    {% endif %}
+                    {% if mapping.is_configured %}
+                    <strong>{{ mapping.display_name }}</strong>
+                    {% else %}
+                    <strong class="text-danger">{{ mapping.server_key }}</strong>
+                    <span class="badge bg-danger-lt ms-1">Not configured</span>
+                    {% endif %}
+                </td>
+                <td>
+                    {% if mapping.device_url %}
+                    <a href="{{ mapping.device_url }}" target="_blank" rel="noopener noreferrer"
+                       class="text-decoration-none">
+                        ID {{ mapping.device_id }}
+                        <i class="mdi mdi-open-in-new ms-1" style="font-size:.8em"></i>
+                    </a>
+                    {% else %}
+                    <span class="text-muted">ID {{ mapping.device_id }}</span>
+                    {% endif %}
+                </td>
+                <td class="text-end pe-3">
+                    {% if not mapping.is_configured %}
+                    {% if lookup_device_model_name == "device" or lookup_device_model_name == "virtualmachine" %}
+                    <form method="post"
+                          action="{% url 'plugins:netbox_librenms_plugin:remove_server_mapping' pk=lookup_device_pk %}"
+                          style="display:inline"
+                          onsubmit="return confirm('Remove mapping for server \'{{ mapping.server_key|escapejs }}\'? This cannot be undone.');">
+                        {% csrf_token %}
+                        <input type="hidden" name="server_key" value="{{ mapping.server_key }}">
+                        <input type="hidden" name="object_type" value="{{ lookup_device_model_name }}">
+                        <button type="submit" class="btn btn-sm btn-danger"
+                                title="Remove stale mapping for unconfigured server '{{ mapping.server_key }}'">
+                            <i class="mdi mdi-trash-can-outline"></i> Remove
+                        </button>
+                    </form>
+                    {% endif %}
+                    {% endif %}
+                </td>
+            </tr>
+            {% endfor %}
+            </tbody>
+        </table>
+    </div>
+</div>
+{% elif librenms_server_info %}
 <div class="card mb-3">
     <div class="card-body p-2">
         <div class="d-flex justify-content-between align-items-center">
@@ -88,7 +153,27 @@ <h5 class="card-header d-flex justify-content-between align-items-center">
                         <!-- LibreNMS ID Row -->
                         <tr>
                             <th scope="row" style="padding-left: 1rem;">ID</th>
-                            <td>{{ librenms_device_id }}</td>
+                            <td>
+                                {{ librenms_device_id }}
+                                {% if librenms_id_is_legacy %}
+                                <form style="display:inline" method="post"
+                                      action="{% url 'plugins:netbox_librenms_plugin:convert_legacy_librenms_id' pk=lookup_device_pk %}">
+                                    {% csrf_token %}
+                                    <input type="hidden" name="object_type" value="{{ lookup_device_model_name }}">
+                                    {% if librenms_id_serial_confirmed %}
+                                    <button type="submit" class="btn btn-sm btn-outline-warning py-0 px-1 ms-1"
+                                            title="Convert legacy ID to server-scoped format">
+                                        <i class="mdi mdi-database-sync"></i> Convert ID
+                                    </button>
+                                    {% else %}
+                                    <button type="button" class="btn btn-sm btn-outline-secondary py-0 px-1 ms-1" disabled
+                                            title="Conversion requires matching NetBox and LibreNMS serial numbers">
+                                        <i class="mdi mdi-database-sync"></i> Convert ID
+                                    </button>
+                                    {% endif %}
+                                </form>
+                                {% endif %}
+                            </td>
                         </tr>
 
                         <!-- Hostname Row -->
@@ -249,7 +334,7 @@ <h5 class="card-header">Device Information Sync</h5>
                                 <div class="d-flex align-items-center">
                                     <div>{{ object.name }}</div>
                                     <div class="ms-3">
-                                        {% if sysName and sysName != object.name %}
+                                        {% if sysName and sysName != "-" and sysName != object.name %}
                                         <form method="post"
                                               action="{% url 'plugins:netbox_librenms_plugin:update_device_name' pk=object.pk %}"
                                               style="display: inline;">
@@ -259,7 +344,7 @@ <h5 class="card-header">Device Information Sync</h5>
                                                 <i class="mdi mdi-sync"></i> Sync to NetBox
                                             </button>
                                         </form>
-                                        {% elif sysName %}
+                                        {% elif sysName and sysName != "-" %}
                                         <span class="text-success" title="Name matches LibreNMS">
                                             <i class="mdi mdi-check-circle"></i>
                                         </span>
@@ -697,6 +782,7 @@ <h5 class="modal-title" id="addDeviceModalLabel">Add Device to LibreNMS</h5>
                 <form method="post" action="{% url 'plugins:netbox_librenms_plugin:add_device_to_librenms' object.id %}"
                     id="snmpv1v2-form" name="snmpv1v2-form" style="display: block;">
                     {% csrf_token %}
+                    <input type="hidden" name="object_type" value="{{ object_model_name }}">
                     <!-- v1/v2c Toggle Button -->
                     <div class="mb-3">
                         <label class="form-label">Protocol Version</label>
@@ -746,6 +832,7 @@ <h5 class="modal-title" id="addDeviceModalLabel">Add Device to LibreNMS</h5>
                 <form method="post" action="{% url 'plugins:netbox_librenms_plugin:add_device_to_librenms' object.id %}"
                     id="snmpv3-form" name="snmpv3-form" style="display: none;">
                     {% csrf_token %}
+                    <input type="hidden" name="object_type" value="{{ object_model_name }}">
                     {{ v3form.snmp_version }}
 
                     <div class="row">
diff --git a/netbox_librenms_plugin/tests/conftest.py b/netbox_librenms_plugin/tests/conftest.py
index c897c5ef56..a6bba487f7 100644
--- a/netbox_librenms_plugin/tests/conftest.py
+++ b/netbox_librenms_plugin/tests/conftest.py
@@ -49,12 +49,10 @@ def mock_librenms_api(mock_multi_server_config):
     """Pre-configured LibreNMSAPI instance with mocked dependencies."""
     with patch("netbox_librenms_plugin.librenms_api.get_plugin_config") as mock_config:
         mock_config.return_value = mock_multi_server_config
-        with patch("netbox_librenms_plugin.librenms_api.LibreNMSSettings") as mock_settings:
-            mock_settings.objects.filter.return_value.first.return_value = None
-            from netbox_librenms_plugin.librenms_api import LibreNMSAPI
+        from netbox_librenms_plugin.librenms_api import LibreNMSAPI
 
-            api = LibreNMSAPI(server_key="default")
-            yield api
+        api = LibreNMSAPI(server_key="default")
+        yield api
 
 
 # =============================================================================
@@ -291,3 +289,48 @@ def mock_netbox_rack():
     rack.name = "Rack A1"
     rack.site = MagicMock(id=1, name="DC1")
     return rack
+
+
+# =============================================================================
+# Server Mapping Fixtures (used by test_sync_view_mismatch.py)
+# =============================================================================
+
+
+@pytest.fixture
+def mock_plugins_config_single_server():
+    """PLUGINS_CONFIG with a single 'production' server (for _build_all_server_mappings tests)."""
+    return {
+        "netbox_librenms_plugin": {
+            "servers": {
+                "production": {
+                    "display_name": "Production LibreNMS",
+                    "librenms_url": "https://librenms.example.com",
+                },
+            }
+        }
+    }
+
+
+@pytest.fixture
+def mock_plugins_config_empty_servers():
+    """PLUGINS_CONFIG with no configured servers (simulates all orphaned)."""
+    return {"netbox_librenms_plugin": {"servers": {}}}
+
+
+@pytest.fixture
+def mock_plugins_config_multi_server_mapping():
+    """PLUGINS_CONFIG with 'production' and 'mock-dev' servers (for multi-server mapping tests)."""
+    return {
+        "netbox_librenms_plugin": {
+            "servers": {
+                "production": {
+                    "display_name": "Production LibreNMS",
+                    "librenms_url": "https://librenms.example.com",
+                },
+                "mock-dev": {
+                    "display_name": "Mock",
+                    "librenms_url": "http://mock.example.com",
+                },
+            }
+        }
+    }
diff --git a/netbox_librenms_plugin/tests/mock_librenms_server.py b/netbox_librenms_plugin/tests/mock_librenms_server.py
index 9c6d06e1f8..588515dfd9 100644
--- a/netbox_librenms_plugin/tests/mock_librenms_server.py
+++ b/netbox_librenms_plugin/tests/mock_librenms_server.py
@@ -199,6 +199,46 @@ def ports_response(self, device_id: int = 1, ports=None):
     def auth_error_response(self, path="/api/v0/devices"):
         self.register(path, {"status": "error", "message": "Authentication failed"}, status=401)
 
+    def inventory_response(self, device_id: int, items: list, status: int = 200):
+        """Register a plain inventory response for /api/v0/inventory/{device_id}/all."""
+        self.register(
+            f"/api/v0/inventory/{device_id}/all",
+            {"status": "ok", "inventory": items},
+            status=status,
+        )
+
+    def vc_inventory_callable(self, device_id: int, root_items: list, children_by_parent_index: dict):
+        """
+        Register a callable route for VC detection two-call pattern.
+
+        detect_virtual_chassis_from_inventory() calls get_inventory_filtered() twice:
+          1. entPhysicalContainedIn=0 → root items
+          2. entPhysicalClass=chassis&entPhysicalContainedIn=<parent_index> → member chassis items
+
+        children_by_parent_index: dict mapping parent index (int) → list of chassis items
+        """
+        root = root_items
+        children = children_by_parent_index
+
+        def _handler(method, path, query, headers, body):
+            contained_in = query.get("entPhysicalContainedIn", [None])[0]
+            if contained_in == "0":
+                return 200, {"status": "ok", "inventory": root}
+            if contained_in is not None:
+                try:
+                    idx = int(contained_in)
+                except (TypeError, ValueError):
+                    return 404, {"status": "error", "message": "bad contained_in"}
+                items = children.get(idx, [])
+                return 200, {"status": "ok", "inventory": items}
+            # No filter → return all (fallback for /all)
+            all_items = list(root)
+            for v in children.values():
+                all_items.extend(v)
+            return 200, {"status": "ok", "inventory": all_items}
+
+        self.routes[f"/api/v0/inventory/{device_id}"] = _handler
+
 
 @contextmanager
 def librenms_mock_server():
diff --git a/netbox_librenms_plugin/tests/test_background_jobs.py b/netbox_librenms_plugin/tests/test_background_jobs.py
index 57014dac0c..88f6931cf7 100644
--- a/netbox_librenms_plugin/tests/test_background_jobs.py
+++ b/netbox_librenms_plugin/tests/test_background_jobs.py
@@ -225,6 +225,7 @@ def test_run_with_custom_server_key(self, mock_process, mock_api_class):
 
         mock_api = MagicMock()
         mock_api.cache_timeout = 300
+        mock_api.server_key = "secondary"
         mock_api_class.return_value = mock_api
         mock_process.return_value = [{"device_id": 1, "hostname": "test1"}]
 
@@ -251,6 +252,7 @@ def test_run_stores_job_data_correctly(self, mock_process, mock_api_class):
 
         mock_api = MagicMock()
         mock_api.cache_timeout = 300
+        mock_api.server_key = "secondary"
         mock_api_class.return_value = mock_api
 
         mock_process.return_value = [
@@ -435,7 +437,9 @@ def test_run_mixed_device_and_vm_import(self, mock_api_class, mock_bulk_devices,
         """Import both devices and VMs."""
         from netbox_librenms_plugin.jobs import ImportDevicesJob
 
-        mock_api_class.return_value = MagicMock()
+        mock_api_instance = MagicMock()
+        mock_api_instance.server_key = "default"
+        mock_api_class.return_value = mock_api_instance
 
         # Mock device imports
         mock_device = MagicMock()
@@ -446,6 +450,7 @@ def test_run_mixed_device_and_vm_import(self, mock_api_class, mock_bulk_devices,
             "failed": [],
             "skipped": [],
             "virtual_chassis_created": 0,
+            "cancelled": False,
         }
 
         # Mock VM imports
@@ -470,6 +475,10 @@ def test_run_mixed_device_and_vm_import(self, mock_api_class, mock_bulk_devices,
         mock_bulk_devices.assert_called_once()
         mock_bulk_vms.assert_called_once()
 
+        # Verify server_key is forwarded to bulk_import_devices_shared
+        bulk_devices_kwargs = mock_bulk_devices.call_args[1]
+        assert bulk_devices_kwargs.get("server_key") == "default"
+
         # Verify combined results
         assert job.job.data["imported_device_pks"] == [100]
         assert job.job.data["imported_vm_pks"] == [200]
@@ -686,6 +695,8 @@ def test_load_success_uses_correct_cache_keys(self, mock_job_class, mock_get_key
             "vc_detection_enabled": True,
             "cached_at": "2026-01-20T10:00:00Z",
             "cache_timeout": 600,
+            "use_sysname": True,
+            "strip_domain": False,
         }
         mock_job_class.objects.get.return_value = mock_job
 
@@ -738,6 +749,8 @@ def test_load_extracts_filters_from_job_data(self, mock_job_class, mock_get_key,
             "vc_detection_enabled": False,
             "cached_at": "2026-01-20T10:00:00Z",
             "cache_timeout": 300,
+            "use_sysname": True,
+            "strip_domain": False,
         }
         mock_job_class.objects.get.return_value = mock_job
         mock_get_key.return_value = "test_key"
diff --git a/netbox_librenms_plugin/tests/test_import_utils.py b/netbox_librenms_plugin/tests/test_import_utils.py
index b112e4deab..7c97ef580c 100644
--- a/netbox_librenms_plugin/tests/test_import_utils.py
+++ b/netbox_librenms_plugin/tests/test_import_utils.py
@@ -36,7 +36,8 @@ def test_get_cache_metadata_key_all_params(self):
         )
 
         assert "production" in key
-        assert "DC1" in key or "location" in key
+        # Filter values are hashed, not embedded directly in the key
+        assert "librenms_filter_cache_metadata" in key
         assert "True" in key or "true" in key.lower()
 
     def test_get_validated_device_cache_key(self):
@@ -65,6 +66,31 @@ def test_get_import_device_cache_key(self):
         assert "secondary" in key
         assert "456" in key
 
+    def test_validated_device_cache_key_unique_per_naming_mode(self):
+        """Different naming preferences produce different cache keys."""
+        from netbox_librenms_plugin.import_utils import get_validated_device_cache_key
+
+        base_args = dict(server_key="default", filters={}, device_id=123, vc_enabled=False)
+        key_default = get_validated_device_cache_key(**base_args)
+        key_no_sysname = get_validated_device_cache_key(**base_args, use_sysname=False)
+        key_strip = get_validated_device_cache_key(**base_args, strip_domain=True)
+
+        assert key_default != key_no_sysname
+        assert key_default != key_strip
+        assert key_no_sysname != key_strip
+
+    def test_cache_metadata_key_unique_per_naming_mode(self):
+        """Different naming preferences produce different metadata cache keys."""
+        from netbox_librenms_plugin.import_utils import get_cache_metadata_key
+
+        base_args = dict(server_key="default", filters={}, vc_enabled=False)
+        key_default = get_cache_metadata_key(**base_args)
+        key_no_sysname = get_cache_metadata_key(**base_args, use_sysname=False)
+        key_strip = get_cache_metadata_key(**base_args, strip_domain=True)
+
+        assert key_default != key_no_sysname
+        assert key_default != key_strip
+
 
 # =============================================================================
 # TestDeviceNameDetermination - 6 tests
@@ -151,7 +177,7 @@ class TestDeviceRetrieval:
     """Test device retrieval and filtering functions."""
 
     @patch("netbox_librenms_plugin.import_utils.filters.cache")
-    @patch("netbox_librenms_plugin.import_utils.device_operations.LibreNMSAPI")
+    @patch("netbox_librenms_plugin.import_utils.filters.LibreNMSAPI")
     def test_get_librenms_devices_for_import_success(self, mock_api_class, mock_cache):
         """Retrieve devices from LibreNMS API."""
         mock_cache.get.return_value = None  # Cache miss
@@ -228,11 +254,11 @@ def test_get_device_count_for_filters_success(self, mock_cache):
 
     @patch("netbox_librenms_plugin.import_utils.filters.cache")
     def test_get_device_count_excludes_disabled(self, mock_cache):
-        """Count respects show_disabled filter parameter."""
+        """Count respects show_disabled filter parameter: disabled==1 devices excluded."""
         mock_cache.get.return_value = [
-            {"device_id": 1, "hostname": "switch-01", "status": 1},
-            {"device_id": 2, "hostname": "switch-02", "status": 1},
-            {"device_id": 3, "hostname": "switch-03", "status": 0},  # disabled
+            {"device_id": 1, "hostname": "switch-01", "disabled": 0, "status": 1},
+            {"device_id": 2, "hostname": "switch-02", "disabled": 0, "status": 0},
+            {"device_id": 3, "hostname": "switch-03", "disabled": 1, "status": 1},  # disabled in LibreNMS
         ]
         mock_api = MagicMock()
 
@@ -243,10 +269,10 @@ def test_get_device_count_excludes_disabled(self, mock_cache):
         assert count == 2
 
     def test_get_import_device_cache_key_default_server(self):
-        """Generate cache key with default server."""
+        """Generate cache key with explicit default server key."""
         from netbox_librenms_plugin.import_utils import get_import_device_cache_key
 
-        key = get_import_device_cache_key(device_id=123)
+        key = get_import_device_cache_key(device_id=123, server_key="default")
 
         assert "default" in key
         assert "123" in key
@@ -342,7 +368,6 @@ def test_validate_device_site_match_found(
         }
         mock_role.objects.all.return_value = []
         mock_cluster.objects.all.return_value = []
-        mock_rack.objects.filter.return_value = []
         mock_site_model.objects.all.return_value = [mock_site]
 
         from netbox_librenms_plugin.import_utils import validate_device_for_import
@@ -400,7 +425,6 @@ def test_validate_device_site_not_found(
         }
         mock_role.objects.all.return_value = []
         mock_cluster.objects.all.return_value = []
-        mock_rack.objects.filter.return_value = []
         mock_site_model.objects.all.return_value = []
 
         from netbox_librenms_plugin.import_utils import validate_device_for_import
@@ -462,7 +486,6 @@ def test_validate_device_platform_match_found(
         }
         mock_role.objects.all.return_value = []
         mock_cluster.objects.all.return_value = []
-        mock_rack.objects.filter.return_value = []
         mock_site_model.objects.all.return_value = []
 
         from netbox_librenms_plugin.import_utils import validate_device_for_import
@@ -520,7 +543,6 @@ def test_validate_device_platform_not_found(
         }
         mock_role.objects.all.return_value = []
         mock_cluster.objects.all.return_value = []
-        mock_rack.objects.filter.return_value = []
         mock_site_model.objects.all.return_value = []
 
         from netbox_librenms_plugin.import_utils import validate_device_for_import
@@ -578,7 +600,6 @@ def test_validate_device_type_match_found(
         }
         mock_role.objects.all.return_value = []
         mock_cluster.objects.all.return_value = []
-        mock_rack.objects.filter.return_value = []
         mock_site_model.objects.all.return_value = []
 
         from netbox_librenms_plugin.import_utils import validate_device_for_import
@@ -639,7 +660,6 @@ def test_validate_device_type_not_found(
         }
         mock_role.objects.all.return_value = []
         mock_cluster.objects.all.return_value = []
-        mock_rack.objects.filter.return_value = []
         mock_site_model.objects.all.return_value = []
 
         from netbox_librenms_plugin.import_utils import validate_device_for_import
@@ -699,7 +719,6 @@ def test_validate_device_role_required(
         }
         mock_role.objects.all.return_value = [MagicMock(id=1, name="Access Switch")]
         mock_cluster.objects.all.return_value = []
-        mock_rack.objects.filter.return_value = []
         mock_site_model.objects.all.return_value = [mock_site]
 
         from netbox_librenms_plugin.import_utils import validate_device_for_import
@@ -758,7 +777,6 @@ def test_validate_device_handles_empty_location(
         }
         mock_role.objects.all.return_value = []
         mock_cluster.objects.all.return_value = []
-        mock_rack.objects.filter.return_value = []
         mock_site_model.objects.all.return_value = []
 
         from netbox_librenms_plugin.import_utils import validate_device_for_import
@@ -817,7 +835,6 @@ def test_validate_device_handles_empty_os(
         }
         mock_role.objects.all.return_value = []
         mock_cluster.objects.all.return_value = []
-        mock_rack.objects.filter.return_value = []
         mock_site_model.objects.all.return_value = []
 
         from netbox_librenms_plugin.import_utils import validate_device_for_import
@@ -878,7 +895,6 @@ def test_validate_device_handles_empty_hardware(
         }
         mock_role.objects.all.return_value = []
         mock_cluster.objects.all.return_value = []
-        mock_rack.objects.filter.return_value = []
         mock_site_model.objects.all.return_value = []
 
         from netbox_librenms_plugin.import_utils import validate_device_for_import
@@ -975,7 +991,6 @@ def test_validate_device_returns_complete_state(
         }
         mock_role.objects.all.return_value = []
         mock_cluster.objects.all.return_value = []
-        mock_rack.objects.filter.return_value = []
         mock_site_model.objects.all.return_value = []
 
         from netbox_librenms_plugin.import_utils import validate_device_for_import
@@ -1001,7 +1016,6 @@ def test_validate_device_returns_complete_state(
         assert "platform" in result
 
     @patch("netbox_librenms_plugin.import_utils.device_operations.cache")
-    @patch("virtualization.models.Cluster")
     @patch("virtualization.models.VirtualMachine")
     @patch("netbox_librenms_plugin.import_utils.device_operations.Device")
     @patch("netbox_librenms_plugin.import_utils.device_operations.find_matching_site")
@@ -1015,14 +1029,13 @@ def test_validate_device_import_as_vm(
         self,
         mock_site_model,
         mock_rack,
-        mock_cluster_module,
+        mock_cluster,
         mock_role,
         mock_match_type,
         mock_find_platform,
         mock_find_site,
         mock_device,
         mock_vm,
-        mock_cluster_local,
         mock_cache,
     ):
         """Import as VM mode uses cluster instead of site/device_type."""
@@ -1046,10 +1059,8 @@ def test_validate_device_import_as_vm(
         }
         mock_role.objects.all.return_value = []
         mock_clusters = [MagicMock(id=1, name="VMware Cluster")]
-        # Cluster is imported at module level in device_operations
-        mock_cluster_module.objects.all.return_value = mock_clusters
+        mock_cluster.objects.all.return_value = mock_clusters
         mock_cache.get.return_value = None  # Force cache miss to trigger Cluster.objects.all()
-        mock_rack.objects.filter.return_value = []
         mock_site_model.objects.all.return_value = []
 
         from netbox_librenms_plugin.import_utils import validate_device_for_import
@@ -1105,7 +1116,7 @@ def test_validate_device_existing_vm_blocks_import(
         assert result["import_as_vm"] is True
 
 
-class TestDeviceNamingPreferences:
+class TestDeviceNamingPreferencesLegacy:
     """Test that validation honours use_sysname and strip_domain user preferences."""
 
     COMMON_PATCHES = [
@@ -1287,7 +1298,7 @@ def test_backward_compatible_defaults(self, *mocks):
         assert result["resolved_name"] == "switch-01"
 
 
-class TestNameMatchesWithNamingPreferences:
+class TestNameMatchesWithNamingPreferencesLegacy:
     """
     Test that name_matches/name_sync_available respect naming preferences and VC patterns.
 
@@ -1345,22 +1356,36 @@ def _configure_standard_mocks(self):
         self.mock_site_model.objects.all.return_value = []
 
     def _setup_librenms_id_match(self, existing_device, as_vm=False):
-        """Configure mocks so that a device is found by librenms_id."""
+        """Configure mocks so that a device is found by librenms_id.
+
+        Uses a Q-aware side_effect so only filter() calls targeting a
+        ``librenms_id`` field return the existing device; other filter() calls
+        (e.g. name lookups, serial lookups) return an empty queryset.
+        """
+        from unittest.mock import MagicMock
+
+        def _librenms_id_filter_side_effect(hit):
+            def side_effect(*args, **kwargs):
+                mock_qs = MagicMock()
+                # Match when the first positional arg is a Q that references librenms_id
+                if args:
+                    q = args[0]
+                    if hasattr(q, "children") and any(
+                        isinstance(child, tuple) and "librenms_id" in child[0] for child in q.children
+                    ):
+                        mock_qs.first.return_value = hit
+                        return mock_qs
+                mock_qs.first.return_value = None
+                return mock_qs
+
+            return side_effect
+
         if as_vm:
-            self.mock_vm.objects.filter.return_value.first.return_value = existing_device
-            self.mock_device.objects.filter.return_value.first.return_value = None
+            self.mock_vm.objects.filter.side_effect = _librenms_id_filter_side_effect(existing_device)
+            self.mock_device.objects.filter.side_effect = _librenms_id_filter_side_effect(None)
         else:
-            self.mock_vm.objects.filter.return_value.first.return_value = None
-
-            def device_filter(**kwargs):
-                result = MagicMock()
-                if "custom_field_data__librenms_id" in kwargs:
-                    result.first.return_value = existing_device
-                else:
-                    result.first.return_value = None
-                return result
-
-            self.mock_device.objects.filter.side_effect = device_filter
+            self.mock_device.objects.filter.side_effect = _librenms_id_filter_side_effect(existing_device)
+            self.mock_vm.objects.filter.side_effect = _librenms_id_filter_side_effect(None)
 
     def setup_method(self):
         """Set up common patches."""
@@ -1605,6 +1630,7 @@ class TestSerialNumberMatching:
         "netbox_librenms_plugin.import_utils.device_operations.Rack",
         "netbox_librenms_plugin.import_utils.device_operations.Cluster",
         "netbox_librenms_plugin.import_utils.device_operations.DeviceRole",
+        "netbox_librenms_plugin.import_utils.device_operations.DeviceType",
         "netbox_librenms_plugin.import_utils.device_operations.match_librenms_hardware_to_device_type",
         "netbox_librenms_plugin.import_utils.device_operations.find_matching_platform",
         "netbox_librenms_plugin.import_utils.device_operations.find_matching_site",
@@ -1621,12 +1647,14 @@ def _start_patches(self):
             self.mock_rack,
             self.mock_cluster,
             self.mock_role,
+            self.mock_device_type,
             self.mock_match_type,
             self.mock_find_platform,
             self.mock_find_site,
             self.mock_device,
             self.mock_vm,
         ) = mocks
+        self.mock_device_type.objects.all.return_value = []
 
     def _stop_patches(self):
         """Stop all patches."""
@@ -1720,7 +1748,7 @@ def device_filter(**kwargs):
 
         assert result["serial_action"] == "hostname_differs"
         assert result["existing_match_type"] == "serial"
-        assert "reinstalled" in result["warnings"][0]
+        assert "hostname differs" in result["warnings"][0]
 
     def test_hostname_match_diff_serial_offers_update(self):
         """Hostname matches but serial differs offers update_serial action."""
@@ -1761,7 +1789,6 @@ def _setup_no_match_mocks(self):
         self.mock_match_type.return_value = {"matched": False, "device_type": None, "match_type": None}
         self.mock_role.objects.all.return_value = []
         self.mock_cluster.objects.all.return_value = []
-        self.mock_rack.objects.filter.return_value = []
         self.mock_site_model.objects.all.return_value = []
 
     def test_serial_dash_ignored(self):
@@ -1837,13 +1864,17 @@ def test_librenms_id_match_shows_serial_confirmed(self):
         existing = MagicMock()
         existing.name = "switch-01"
         existing.serial = "ABC123"
-        existing.virtual_chassis = None
+        existing.virtual_chassis = None  # Not a VC member → use plain hostname comparison
+        existing.vc_position = None
 
         self.mock_vm.objects.filter.return_value.first.return_value = None
 
-        def device_filter(**kwargs):
+        def device_filter(*args, **kwargs):
             result = MagicMock()
-            if "custom_field_data__librenms_id" in kwargs:
+            q_has_librenms = any("librenms_id" in str(arg) for arg in args) or any(
+                k.startswith("custom_field_data__librenms_id") for k in kwargs
+            )
+            if q_has_librenms:
                 result.first.return_value = existing
             else:
                 result.first.return_value = None
@@ -1860,7 +1891,6 @@ def device_filter(**kwargs):
         self.mock_match_type.return_value = {"matched": False, "device_type": None, "match_type": None}
         self.mock_role.objects.all.return_value = []
         self.mock_cluster.objects.all.return_value = []
-        self.mock_rack.objects.filter.return_value = []
         self.mock_site_model.objects.all.return_value = []
 
         from netbox_librenms_plugin.import_utils import validate_device_for_import
@@ -1878,12 +1908,17 @@ def test_librenms_id_match_detects_serial_drift(self):
         existing = MagicMock()
         existing.name = "switch-01"
         existing.serial = "OLD_SERIAL"
+        existing.virtual_chassis = None
+        existing.vc_position = None
 
         self.mock_vm.objects.filter.return_value.first.return_value = None
 
-        def device_filter(**kwargs):
+        def device_filter(*args, **kwargs):
             result = MagicMock()
-            if "custom_field_data__librenms_id" in kwargs:
+            q_has_librenms = any("librenms_id" in str(arg) for arg in args) or any(
+                k.startswith("custom_field_data__librenms_id") for k in kwargs
+            )
+            if q_has_librenms:
                 result.first.return_value = existing
             elif "serial" in kwargs:
                 result.first.return_value = None
@@ -1903,7 +1938,6 @@ def device_filter(**kwargs):
         self.mock_match_type.return_value = {"matched": False, "device_type": None, "match_type": None}
         self.mock_role.objects.all.return_value = []
         self.mock_cluster.objects.all.return_value = []
-        self.mock_rack.objects.filter.return_value = []
         self.mock_site_model.objects.all.return_value = []
 
         from netbox_librenms_plugin.import_utils import validate_device_for_import
@@ -1920,12 +1954,17 @@ def test_librenms_id_match_still_validates_site(self):
         existing = MagicMock()
         existing.name = "switch-01"
         existing.serial = ""
+        existing.virtual_chassis = None
+        existing.vc_position = None
 
         self.mock_vm.objects.filter.return_value.first.return_value = None
 
-        def device_filter(**kwargs):
+        def device_filter(*args, **kwargs):
             result = MagicMock()
-            if "custom_field_data__librenms_id" in kwargs:
+            q_has_librenms = any("librenms_id" in str(arg) for arg in args) or any(
+                k.startswith("custom_field_data__librenms_id") for k in kwargs
+            )
+            if q_has_librenms:
                 result.first.return_value = existing
             else:
                 result.first.return_value = None
@@ -1939,7 +1978,6 @@ def device_filter(**kwargs):
         self.mock_match_type.return_value = {"matched": True, "device_type": mock_dt, "match_type": "exact"}
         self.mock_role.objects.all.return_value = []
         self.mock_cluster.objects.all.return_value = []
-        self.mock_rack.objects.filter.return_value = []
         self.mock_site_model.objects.all.return_value = []
 
         from netbox_librenms_plugin.import_utils import validate_device_for_import
@@ -1960,6 +1998,8 @@ def test_existing_device_role_populated(self):
         existing = MagicMock()
         existing.name = "switch-01"
         existing.serial = "ABC123"
+        existing.virtual_chassis = None
+        existing.vc_position = None
         mock_existing_role = MagicMock()
         mock_existing_role.name = "Access Switch"
         existing.role = mock_existing_role
@@ -1980,7 +2020,6 @@ def device_filter(**kwargs):
         self.mock_match_type.return_value = {"matched": True, "device_type": MagicMock(), "match_type": "exact"}
         self.mock_role.objects.all.return_value = [mock_existing_role]
         self.mock_cluster.objects.all.return_value = []
-        self.mock_rack.objects.filter.return_value = []
         self.mock_site_model.objects.all.return_value = []
 
         with patch("netbox_librenms_plugin.import_utils.device_operations.cache") as mock_cache:
@@ -2006,6 +2045,8 @@ def test_device_type_mismatch_flagged(self):
         existing = MagicMock()
         existing.name = "switch-01"
         existing.serial = "ABC123"
+        existing.virtual_chassis = None
+        existing.vc_position = None
         existing_device_type = MagicMock()
         existing_device_type.pk = 1
         existing_device_type.__str__ = lambda self: "Old Type"
@@ -2036,7 +2077,6 @@ def device_filter(**kwargs):
         }
         self.mock_role.objects.all.return_value = []
         self.mock_cluster.objects.all.return_value = []
-        self.mock_rack.objects.filter.return_value = []
         self.mock_site_model.objects.all.return_value = []
 
         with patch("netbox_librenms_plugin.import_utils.device_operations.cache") as mock_cache:
@@ -2061,6 +2101,8 @@ def test_no_device_type_mismatch_when_types_match(self):
         existing = MagicMock()
         existing.name = "switch-01"
         existing.serial = "ABC123"
+        existing.virtual_chassis = None
+        existing.vc_position = None
         same_device_type = MagicMock()
         same_device_type.pk = 1
         existing.device_type = same_device_type
@@ -2082,7 +2124,6 @@ def device_filter(**kwargs):
         self.mock_match_type.return_value = {"matched": True, "device_type": same_device_type, "match_type": "exact"}
         self.mock_role.objects.all.return_value = []
         self.mock_cluster.objects.all.return_value = []
-        self.mock_rack.objects.filter.return_value = []
         self.mock_site_model.objects.all.return_value = []
 
         with patch("netbox_librenms_plugin.import_utils.device_operations.cache") as mock_cache:
@@ -2102,221 +2143,451 @@ def device_filter(**kwargs):
         assert result["device_type_mismatch"] is False
 
 
-class TestDeviceConflictActionView:
-    """Test DeviceConflictActionView conflict resolution actions."""
+class TestNameMatchesWithNamingPreferences:
+    """Test VC-aware name matching with use_sysname/strip_domain preferences."""
 
-    def _create_view(self):
-        """Create a DeviceConflictActionView instance with mocked dependencies."""
-        from netbox_librenms_plugin.views.imports.actions import DeviceConflictActionView
+    PATCHES = [
+        "netbox_librenms_plugin.import_utils.device_operations.Site",
+        "netbox_librenms_plugin.import_utils.device_operations.Rack",
+        "netbox_librenms_plugin.import_utils.device_operations.Cluster",
+        "netbox_librenms_plugin.import_utils.device_operations.DeviceRole",
+        "netbox_librenms_plugin.import_utils.device_operations.DeviceType",
+        "netbox_librenms_plugin.import_utils.device_operations.match_librenms_hardware_to_device_type",
+        "netbox_librenms_plugin.import_utils.device_operations.find_matching_platform",
+        "netbox_librenms_plugin.import_utils.device_operations.find_matching_site",
+        "netbox_librenms_plugin.import_utils.device_operations.Device",
+        "virtualization.models.VirtualMachine",
+    ]
 
-        view = object.__new__(DeviceConflictActionView)
-        view._librenms_api = MagicMock()
-        view._librenms_api.server_key = "default"
-        view.request = MagicMock()
-        view.request.user.has_perm.return_value = True
-        return view
+    def setup_method(self):
+        self._patchers = [patch(p) for p in self.PATCHES]
+        mocks = [p.start() for p in self._patchers]
+        (
+            self.mock_site,
+            self.mock_rack,
+            self.mock_cluster,
+            self.mock_role,
+            self.mock_device_type,
+            self.mock_match_type,
+            self.mock_find_platform,
+            self.mock_find_site,
+            self.mock_device,
+            self.mock_vm,
+        ) = mocks
+        self.mock_device_type.objects.all.return_value = []
+        self.mock_vm.objects.filter.return_value.first.return_value = None
+        self.mock_find_site.return_value = {
+            "found": True,
+            "site": MagicMock(),
+            "match_type": "exact",
+            "confidence": 1.0,
+        }
+        self.mock_find_platform.return_value = {"found": False, "platform": None, "match_type": None}
+        self.mock_match_type.return_value = {"matched": False, "device_type": None, "match_type": None}
+        self.mock_role.objects.all.return_value = []
+        self.mock_cluster.objects.all.return_value = []
+        self.mock_site.objects.all.return_value = []
 
-    def _create_request(self, action, existing_device_id, use_sysname=False, strip_domain=False):
-        """Create a mock request with POST data."""
-        request = MagicMock()
-        post_data = {"action": action, "existing_device_id": str(existing_device_id)}
-        if use_sysname:
-            post_data["use-sysname-toggle"] = "on"
-        if strip_domain:
-            post_data["strip-domain-toggle"] = "on"
-        request.POST = post_data
-        return request
+    def teardown_method(self):
+        for p in self._patchers:
+            p.stop()
 
-    @patch("netbox_librenms_plugin.views.imports.actions.cache")
-    @patch("netbox_librenms_plugin.views.imports.actions.get_import_device_cache_key")
-    def test_link_action_sets_librenms_id_and_name(self, mock_cache_key, mock_cache):
-        """Link action should set librenms_id and update name from sysName."""
-        from netbox_librenms_plugin.views.imports.actions import DeviceConflictActionView
+    def _make_existing(self, name, serial="SN001", virtual_chassis=None, vc_position=None):
+        existing = MagicMock()
+        existing.name = name
+        existing.serial = serial
+        existing.virtual_chassis = virtual_chassis
+        existing.vc_position = vc_position
+        existing.custom_field_data = {"librenms_id": {"default": 42}}
+        return existing
+
+    def _setup_librenms_id_filter(self, existing):
+        def device_filter(*args, **kwargs):
+            result = MagicMock()
+            q_has_librenms = any("librenms_id" in str(arg) for arg in args) or any(
+                k.startswith("custom_field_data__librenms_id") for k in kwargs
+            )
+            result.first.return_value = existing if q_has_librenms else None
+            result.exclude.return_value.first.return_value = None
+            return result
 
-        view = self._create_view()
-        existing_device = MagicMock()
-        existing_device.pk = 42
-        existing_device.custom_field_data = {}
-        existing_device.name = "84.116.251.35"
+        self.mock_device.objects.filter.side_effect = device_filter
 
-        libre_device = {
-            "device_id": 10,
-            "hostname": "84.116.251.35",
+    def test_strip_domain_name_matches(self):
+        """strip_domain=True resolves 'switch-01.example.com' to 'switch-01', matching existing device."""
+        from netbox_librenms_plugin.import_utils import validate_device_for_import
+
+        existing = self._make_existing("switch-01")
+        self._setup_librenms_id_filter(existing)
+
+        device_data = {
+            "device_id": 42,
+            "hostname": "switch-01.example.com",
             "sysName": "switch-01.example.com",
-            "serial": "ABC123",
+            "serial": "SN001",
         }
-        validation = {"can_import": False, "existing_device": existing_device}
-        selections = {}
-
-        request = self._create_request("link", 42, use_sysname=True)
+        result = validate_device_for_import(device_data, include_vc_detection=False, strip_domain=True)
+        assert result["name_matches"] is True
+        assert result["name_sync_available"] is False
 
-        with (
-            patch.object(DeviceConflictActionView, "get_validated_device_with_selections") as mock_validate,
-            patch.object(DeviceConflictActionView, "render_device_row") as mock_render,
-            patch("dcim.models.Device") as mock_device_cls,
-        ):
-            mock_device_cls.objects.get.return_value = existing_device
-            mock_device_cls.objects.filter.return_value.exclude.return_value.first.return_value = None
-            mock_validate.return_value = (libre_device, validation, selections)
-            mock_render.return_value = MagicMock()
+    def test_sysname_disabled_uses_hostname(self):
+        """use_sysname=False falls back to hostname for name comparison."""
+        from netbox_librenms_plugin.import_utils import validate_device_for_import
 
-            view.post(request, device_id=10)
+        existing = self._make_existing("switch-hostname")
+        self._setup_librenms_id_filter(existing)
 
-        assert existing_device.custom_field_data["librenms_id"] == 10
-        assert existing_device.name == "switch-01.example.com"
-        existing_device.save.assert_called_once()
+        device_data = {
+            "device_id": 42,
+            "hostname": "switch-hostname",
+            "sysName": "switch-sysname",
+            "serial": "SN001",
+        }
+        result = validate_device_for_import(device_data, include_vc_detection=False, use_sysname=False)
+        assert result["name_matches"] is True
+        assert result["resolved_name"] == "switch-hostname"
 
-    @patch("netbox_librenms_plugin.views.imports.actions.cache")
-    @patch("netbox_librenms_plugin.views.imports.actions.get_import_device_cache_key")
-    def test_update_action_sets_hostname_serial_and_librenms_id(self, mock_cache_key, mock_cache):
-        """Update action should set hostname, serial, and librenms_id."""
-        from netbox_librenms_plugin.views.imports.actions import DeviceConflictActionView
+    def test_name_mismatch_offers_sync(self):
+        """When resolved name differs from existing device name, name_sync_available is set."""
+        from netbox_librenms_plugin.import_utils import validate_device_for_import
 
-        view = self._create_view()
-        existing_device = MagicMock()
-        existing_device.pk = 42
-        existing_device.custom_field_data = {}
-        existing_device.name = "old-name"
-        existing_device.serial = "OLD-SERIAL"
+        existing = self._make_existing("old-name")
+        self._setup_librenms_id_filter(existing)
 
-        libre_device = {
-            "device_id": 10,
-            "hostname": "84.116.251.35",
-            "sysName": "new-name.example.com",
-            "serial": "NEW-SERIAL",
+        device_data = {
+            "device_id": 42,
+            "hostname": "new-name",
+            "sysName": "new-name",
+            "serial": "SN001",
         }
-        validation = {"can_import": False, "existing_device": existing_device}
-        selections = {}
-
-        request = self._create_request("update", 42, use_sysname=True)
+        result = validate_device_for_import(device_data, include_vc_detection=False)
+        assert result["name_matches"] is False
+        assert result["name_sync_available"] is True
+        assert result["suggested_name"] == "new-name"
 
-        with (
-            patch.object(DeviceConflictActionView, "get_validated_device_with_selections") as mock_validate,
-            patch.object(DeviceConflictActionView, "render_device_row") as mock_render,
-            patch("dcim.models.Device") as mock_device_cls,
-        ):
-            mock_device_cls.objects.get.return_value = existing_device
-            mock_device_cls.objects.filter.return_value.exclude.return_value.first.return_value = None
-            mock_validate.return_value = (libre_device, validation, selections)
-            mock_render.return_value = MagicMock()
+    def test_vc_member_name_matches(self):
+        """Existing VC member name is compared against vc_member_name(hostname, vc_position)."""
+        from netbox_librenms_plugin.import_utils import validate_device_for_import
+        from netbox_librenms_plugin.import_utils.virtual_chassis import _generate_vc_member_name
 
-            view.post(request, device_id=10)
+        mock_vc = MagicMock()
+        expected_name = _generate_vc_member_name("stack-master", 2, serial="SN001")
+        existing = self._make_existing(expected_name, serial="SN001", virtual_chassis=mock_vc, vc_position=2)
+        self._setup_librenms_id_filter(existing)
 
-        assert existing_device.custom_field_data["librenms_id"] == 10
-        assert existing_device.serial == "NEW-SERIAL"
-        assert existing_device.name == "new-name.example.com"
-        existing_device.save.assert_called_once()
+        device_data = {
+            "device_id": 42,
+            "hostname": "stack-master",
+            "sysName": "stack-master",
+            "serial": "SN001",
+        }
+        result = validate_device_for_import(device_data, include_vc_detection=False)
+        assert result["name_matches"] is True
 
-    @patch("netbox_librenms_plugin.views.imports.actions.cache")
-    @patch("netbox_librenms_plugin.views.imports.actions.get_import_device_cache_key")
-    def test_update_serial_action_updates_serial_only(self, mock_cache_key, mock_cache):
-        """Update serial action should update serial and librenms_id but not hostname."""
-        from netbox_librenms_plugin.views.imports.actions import DeviceConflictActionView
+    def test_vc_member_name_mismatch_suggests_vc_name(self):
+        """When VC member name differs, suggested_name is the expected VC member name."""
+        from netbox_librenms_plugin.import_utils import validate_device_for_import
+        from netbox_librenms_plugin.import_utils.virtual_chassis import _generate_vc_member_name
 
-        view = self._create_view()
-        existing_device = MagicMock()
-        existing_device.pk = 42
-        existing_device.custom_field_data = {}
-        existing_device.name = "switch-01"
-        existing_device.serial = "OLD-SERIAL"
+        mock_vc = MagicMock()
+        existing = self._make_existing("wrong-name", serial="SN001", virtual_chassis=mock_vc, vc_position=2)
+        self._setup_librenms_id_filter(existing)
 
-        libre_device = {"device_id": 10, "hostname": "switch-01", "serial": "NEW-SERIAL"}
-        validation = {"can_import": False, "existing_device": existing_device}
-        selections = {}
+        device_data = {
+            "device_id": 42,
+            "hostname": "stack-master",
+            "sysName": "stack-master",
+            "serial": "SN001",
+        }
+        result = validate_device_for_import(device_data, include_vc_detection=False)
+        expected_name = _generate_vc_member_name("stack-master", 2, serial="SN001")
+        assert result["name_matches"] is False
+        assert result["name_sync_available"] is True
+        assert result["suggested_name"] == expected_name
 
-        request = self._create_request("update_serial", 42)
+    def test_vc_member_with_strip_domain(self):
+        """strip_domain applies before VC member name comparison."""
+        from netbox_librenms_plugin.import_utils import validate_device_for_import
+        from netbox_librenms_plugin.import_utils.virtual_chassis import _generate_vc_member_name
 
-        with (
-            patch.object(DeviceConflictActionView, "get_validated_device_with_selections") as mock_validate,
-            patch.object(DeviceConflictActionView, "render_device_row") as mock_render,
-            patch("dcim.models.Device") as mock_device_cls,
-        ):
-            mock_device_cls.objects.get.return_value = existing_device
-            mock_device_cls.objects.filter.return_value.exclude.return_value.first.return_value = None
-            mock_validate.return_value = (libre_device, validation, selections)
-            mock_render.return_value = MagicMock()
+        mock_vc = MagicMock()
+        expected_name = _generate_vc_member_name("stack", 1, serial="SN001")
+        existing = self._make_existing(expected_name, serial="SN001", virtual_chassis=mock_vc, vc_position=1)
+        self._setup_librenms_id_filter(existing)
 
-            view.post(request, device_id=10)
+        device_data = {
+            "device_id": 42,
+            "hostname": "stack.example.com",
+            "sysName": "stack.example.com",
+            "serial": "SN001",
+        }
+        result = validate_device_for_import(device_data, include_vc_detection=False, strip_domain=True)
+        assert result["name_matches"] is True
 
-        assert existing_device.custom_field_data["librenms_id"] == 10
-        assert existing_device.serial == "NEW-SERIAL"
-        # Name should NOT be changed by update_serial
-        assert existing_device.name == "switch-01"
-        existing_device.save.assert_called_once()
+    def test_naming_criteria_populated(self):
+        """naming_criteria dict is set in result with use_sysname/strip_domain/source."""
+        from netbox_librenms_plugin.import_utils import validate_device_for_import
 
-    @patch("netbox_librenms_plugin.views.imports.actions.cache")
-    @patch("netbox_librenms_plugin.views.imports.actions.get_import_device_cache_key")
-    def test_update_skips_dash_serial(self, mock_cache_key, mock_cache):
-        """Update should not set serial to '-' (LibreNMS placeholder)."""
-        from netbox_librenms_plugin.views.imports.actions import DeviceConflictActionView
+        self.mock_device.objects.filter.return_value.first.return_value = None
 
-        view = self._create_view()
-        existing_device = MagicMock()
-        existing_device.pk = 42
-        existing_device.custom_field_data = {}
-        existing_device.name = "switch-01"
-        existing_device.serial = "EXISTING"
+        device_data = {
+            "device_id": 99,
+            "hostname": "router-01",
+            "sysName": "router-sysname",
+        }
+        result = validate_device_for_import(
+            device_data, include_vc_detection=False, use_sysname=True, strip_domain=False
+        )
+        criteria = result["naming_criteria"]
+        assert criteria is not None
+        assert criteria["use_sysname"] is True
+        assert criteria["strip_domain"] is False
+        assert criteria["raw_sysname"] == "router-sysname"
+        assert criteria["raw_hostname"] == "router-01"
+        assert criteria["source"] == "sysname"
+
+    def test_naming_criteria_source_hostname_when_sysname_disabled(self):
+        """naming_criteria source is 'hostname' when use_sysname=False."""
+        from netbox_librenms_plugin.import_utils import validate_device_for_import
 
-        libre_device = {"device_id": 10, "hostname": "switch-01", "serial": "-"}
-        validation = {"can_import": False, "existing_device": existing_device}
-        selections = {}
+        self.mock_device.objects.filter.return_value.first.return_value = None
 
-        request = self._create_request("update_serial", 42)
+        device_data = {
+            "device_id": 99,
+            "hostname": "router-01",
+            "sysName": "router-sysname",
+        }
+        result = validate_device_for_import(
+            device_data, include_vc_detection=False, use_sysname=False, strip_domain=False
+        )
+        assert result["naming_criteria"]["source"] == "hostname"
 
-        with (
-            patch.object(DeviceConflictActionView, "get_validated_device_with_selections") as mock_validate,
-            patch.object(DeviceConflictActionView, "render_device_row") as mock_render,
-            patch("dcim.models.Device") as mock_device_cls,
-        ):
-            mock_device_cls.objects.get.return_value = existing_device
-            mock_validate.return_value = (libre_device, validation, selections)
-            mock_render.return_value = MagicMock()
+    def test_naming_criteria_source_sysname_when_sysname_disabled_but_hostname_empty(self):
+        """
+        When use_sysname=False and hostname is empty, source falls back to 'sysname'.
 
-            view.post(request, device_id=10)
+        Before the fix, source was incorrectly reported as 'hostname' even
+        though the resolved name actually came from sysName.
+        """
+        from netbox_librenms_plugin.import_utils import validate_device_for_import
 
-        # Serial should NOT be updated to '-'
-        assert existing_device.serial == "EXISTING"
+        self.mock_device.objects.filter.return_value.first.return_value = None
 
-    def test_missing_action_returns_400(self):
-        """Missing action or existing_device_id should return 400."""
-        view = self._create_view()
-        request = MagicMock()
-        request.POST = {}
+        device_data = {
+            "device_id": 99,
+            "hostname": "",
+            "sysName": "router-sysname",
+        }
+        result = validate_device_for_import(
+            device_data, include_vc_detection=False, use_sysname=False, strip_domain=False
+        )
+        assert result["naming_criteria"]["source"] == "sysname", (
+            "When hostname is empty, source must be 'sysname', not 'hostname'"
+        )
 
-        response = view.post(request, device_id=10)
-        assert response.status_code == 400
+    def test_naming_criteria_source_hostname_fallback_when_both_empty(self):
+        """When both hostname and sysName are empty, source is 'device-{id}' (no-name guard)."""
+        from netbox_librenms_plugin.import_utils import validate_device_for_import
 
-    def test_unknown_action_returns_400(self):
-        """Unknown action should return 400."""
-        from netbox_librenms_plugin.views.imports.actions import DeviceConflictActionView
+        self.mock_device.objects.filter.return_value.first.return_value = None
 
-        view = self._create_view()
-        request = self._create_request("invalid_action", 42)
+        device_data = {"device_id": 99, "hostname": "", "sysName": ""}
+        result = validate_device_for_import(
+            device_data, include_vc_detection=False, use_sysname=False, strip_domain=False
+        )
+        # Both empty → no-name guard returns 'device-{id}' as source
+        assert result["naming_criteria"]["source"] == "device-99"
 
-        existing_device = MagicMock()
-        libre_device = {"device_id": 10, "hostname": "switch-01", "serial": "ABC"}
 
-        with (
-            patch.object(DeviceConflictActionView, "get_validated_device_with_selections") as mock_validate,
-            patch("dcim.models.Device") as mock_device_cls,
-        ):
-            mock_device_cls.objects.get.return_value = existing_device
-            mock_validate.return_value = (libre_device, {}, {})
+class TestLegacyLibreNMSIdMigration:
+    """Test detection of legacy bare-integer librenms_id format during device validation."""
 
-            response = view.post(request, device_id=10)
+    PATCHES = [
+        "netbox_librenms_plugin.import_utils.device_operations.Site",
+        "netbox_librenms_plugin.import_utils.device_operations.Rack",
+        "netbox_librenms_plugin.import_utils.device_operations.Cluster",
+        "netbox_librenms_plugin.import_utils.device_operations.DeviceRole",
+        "netbox_librenms_plugin.import_utils.device_operations.match_librenms_hardware_to_device_type",
+        "netbox_librenms_plugin.import_utils.device_operations.find_matching_platform",
+        "netbox_librenms_plugin.import_utils.device_operations.find_matching_site",
+        "netbox_librenms_plugin.import_utils.device_operations.Device",
+        "virtualization.models.VirtualMachine",
+    ]
 
-        assert response.status_code == 400
+    def setup_method(self):
+        self._patchers = [patch(p) for p in self.PATCHES]
+        mocks = [p.start() for p in self._patchers]
+        (
+            self.mock_site_model,
+            self.mock_rack,
+            self.mock_cluster,
+            self.mock_role,
+            self.mock_match_type,
+            self.mock_find_platform,
+            self.mock_find_site,
+            self.mock_device,
+            self.mock_vm,
+        ) = mocks
+
+        self.mock_find_site.return_value = {
+            "found": True,
+            "site": MagicMock(),
+            "match_type": "exact",
+            "confidence": 1.0,
+        }
+        self.mock_find_platform.return_value = {"found": False, "platform": None, "match_type": None}
+        self.mock_match_type.return_value = {"matched": False, "device_type": None, "match_type": None}
+        self.mock_role.objects.all.return_value = []
+        self.mock_cluster.objects.all.return_value = []
+        self.mock_site_model.objects.all.return_value = []
+        self.mock_vm.objects.filter.return_value.first.return_value = None
+
+    def teardown_method(self):
+        for p in self._patchers:
+            p.stop()
+
+    def _make_existing(self, librenms_id_value, serial="SN001"):
+        existing = MagicMock()
+        existing.name = "switch-01"
+        existing.serial = serial
+        existing.virtual_chassis = None
+        existing.vc_position = None
+        existing.custom_field_data = {"librenms_id": librenms_id_value}
+        return existing
+
+    def _setup_device_filter(self, existing):
+        def device_filter(*args, **kwargs):
+            result = MagicMock()
+            q_has_librenms = any("librenms_id" in str(arg) for arg in args) or any(
+                k.startswith("custom_field_data__librenms_id") for k in kwargs
+            )
+            result.first.return_value = existing if q_has_librenms else None
+            return result
+
+        self.mock_device.objects.filter.side_effect = device_filter
+
+    def test_legacy_int_sets_needs_migration_flag(self):
+        """Device with bare-integer librenms_id sets librenms_id_needs_migration=True."""
+        existing = self._make_existing(librenms_id_value=42, serial="SN001")
+        self._setup_device_filter(existing)
+
+        from netbox_librenms_plugin.import_utils import validate_device_for_import
+
+        result = validate_device_for_import(
+            {"device_id": 42, "hostname": "switch-01", "serial": "SN001"},
+            include_vc_detection=False,
+        )
+
+        assert result["existing_match_type"] == "librenms_id"
+        assert result["librenms_id_needs_migration"] is True
+        assert result["serial_confirmed"] is True
+
+    def test_legacy_int_no_serial_still_sets_flag(self):
+        """Legacy int format sets the migration flag even when serial is absent."""
+        existing = self._make_existing(librenms_id_value=42, serial="")
+        self._setup_device_filter(existing)
+
+        from netbox_librenms_plugin.import_utils import validate_device_for_import
+
+        result = validate_device_for_import(
+            {"device_id": 42, "hostname": "switch-01"},
+            include_vc_detection=False,
+        )
+
+        assert result["librenms_id_needs_migration"] is True
+        assert result["serial_confirmed"] is False
+
+    def test_json_format_does_not_set_flag(self):
+        """Device with JSON librenms_id does NOT set librenms_id_needs_migration."""
+        existing = self._make_existing(librenms_id_value={"default": 42}, serial="SN001")
+        self._setup_device_filter(existing)
+
+        from netbox_librenms_plugin.import_utils import validate_device_for_import
+
+        result = validate_device_for_import(
+            {"device_id": 42, "hostname": "switch-01", "serial": "SN001"},
+            include_vc_detection=False,
+        )
+
+        assert result["existing_match_type"] == "librenms_id"
+        assert result["librenms_id_needs_migration"] is False
+
+    def test_migrate_legacy_librenms_id_helper(self):
+        """migrate_legacy_librenms_id converts int to {server_key: int}."""
+        from netbox_librenms_plugin.utils import migrate_legacy_librenms_id
+
+        obj = MagicMock()
+        obj.custom_field_data = {"librenms_id": 42}
+        result = migrate_legacy_librenms_id(obj, "primary")
+
+        assert result is True
+        assert obj.custom_field_data["librenms_id"] == {"primary": 42}
+
+    def test_migrate_legacy_librenms_id_noop_for_json(self):
+        """migrate_legacy_librenms_id is a no-op when value is already a dict."""
+        from netbox_librenms_plugin.utils import migrate_legacy_librenms_id
+
+        obj = MagicMock()
+        obj.custom_field_data = {"librenms_id": {"primary": 42}}
+        result = migrate_legacy_librenms_id(obj, "primary")
+
+        assert result is False
+        assert obj.custom_field_data["librenms_id"] == {"primary": 42}
+
+    def test_migrate_legacy_librenms_id_noop_for_none(self):
+        """migrate_legacy_librenms_id is a no-op when librenms_id is absent."""
+        from netbox_librenms_plugin.utils import migrate_legacy_librenms_id
+
+        obj = MagicMock()
+        obj.custom_field_data = {}
+        result = migrate_legacy_librenms_id(obj, "primary")
+
+        assert result is False
+
+
+class TestDeviceConflictActionView:
+    """Test DeviceConflictActionView conflict resolution actions."""
+
+    def _create_view(self):
+        """Create a DeviceConflictActionView instance with mocked dependencies."""
+        from netbox_librenms_plugin.views.imports.actions import DeviceConflictActionView
+
+        view = DeviceConflictActionView()
+        view._librenms_api = MagicMock()
+        view._librenms_api.server_key = "default"
+        return view
+
+    def _create_request(self, action, existing_device_id, use_sysname=False, strip_domain=False):
+        """
+        Create a mock request with POST data and permission stubs.
+
+        The returned request should be bound to the view (view.request = request)
+        before calling view.post() so permission checks and business logic
+        operate on the same request object, matching real Django CBV behavior.
+        """
+        request = MagicMock()
+        request.user.has_perm.return_value = True
+        # Always include both toggles so _resolve_naming_preferences never falls through
+        # to the user-pref/settings DB path, which would hit the real database.
+        post_data = {
+            "action": action,
+            "existing_device_id": str(existing_device_id),
+            "use-sysname-toggle": "on" if use_sysname else "off",
+            "strip-domain-toggle": "on" if strip_domain else "off",
+        }
+        request.POST = post_data
+        return request
 
     @patch("netbox_librenms_plugin.views.imports.actions.cache")
     @patch("netbox_librenms_plugin.views.imports.actions.get_import_device_cache_key")
-    def test_sync_name_action_updates_name(self, mock_cache_key, mock_cache):
-        """Sync name action should update device name using sysName."""
+    def test_link_action_sets_librenms_id_and_name(self, mock_cache_key, mock_cache):
+        """Link action should set librenms_id and update name from sysName."""
         from netbox_librenms_plugin.views.imports.actions import DeviceConflictActionView
 
         view = self._create_view()
         existing_device = MagicMock()
         existing_device.pk = 42
-        existing_device.custom_field_data = {"librenms_id": 10}
+        existing_device.custom_field_data = {}
         existing_device.name = "84.116.251.35"
 
         libre_device = {
@@ -2328,55 +2599,79 @@ def test_sync_name_action_updates_name(self, mock_cache_key, mock_cache):
         validation = {"can_import": False, "existing_device": existing_device}
         selections = {}
 
-        request = self._create_request("sync_name", 42, use_sysname=True)
+        request = self._create_request("link", 42, use_sysname=True)
 
         with (
             patch.object(DeviceConflictActionView, "get_validated_device_with_selections") as mock_validate,
             patch.object(DeviceConflictActionView, "render_device_row") as mock_render,
             patch("dcim.models.Device") as mock_device_cls,
+            patch("netbox_librenms_plugin.views.imports.actions.transaction") as mock_tx,
         ):
+            mock_tx.atomic.return_value = MagicMock()
             mock_device_cls.objects.get.return_value = existing_device
+            mock_device_cls.objects.select_for_update.return_value.get.return_value = existing_device
+            mock_device_cls.objects.select_for_update.return_value.filter.return_value.exclude.return_value.first.return_value = None
+            mock_device_cls.objects.filter.return_value.first.return_value = None
+            mock_device_cls.objects.filter.return_value.exclude.return_value.first.return_value = None
+            mock_device_cls.objects.filter.return_value.exclude.return_value.exists.return_value = False
             mock_validate.return_value = (libre_device, validation, selections)
             mock_render.return_value = MagicMock()
 
+            view.request = request
             view.post(request, device_id=10)
 
+        assert existing_device.custom_field_data["librenms_id"] == {"default": 10}
         assert existing_device.name == "switch-01.example.com"
         existing_device.save.assert_called_once()
 
     @patch("netbox_librenms_plugin.views.imports.actions.cache")
     @patch("netbox_librenms_plugin.views.imports.actions.get_import_device_cache_key")
-    def test_device_type_mismatch_blocked_without_force(self, mock_cache_key, mock_cache):
-        """Action should be blocked when device_type_mismatch is True and force is not set."""
+    def test_link_action_uses_non_default_server_key(self, mock_cache_key, mock_cache):
+        """Link action should store librenms_id under the active server_key, not always 'default'."""
         from netbox_librenms_plugin.views.imports.actions import DeviceConflictActionView
 
         view = self._create_view()
+        view._librenms_api.server_key = "production"
         existing_device = MagicMock()
         existing_device.pk = 42
         existing_device.custom_field_data = {}
+        existing_device.name = "84.116.251.35"
 
-        libre_device = {"device_id": 10, "hostname": "switch-01", "serial": "ABC123"}
-        validation = {"can_import": False, "device_type_mismatch": True, "existing_device": existing_device}
+        libre_device = {
+            "device_id": 10,
+            "hostname": "84.116.251.35",
+            "sysName": "switch-01.example.com",
+            "serial": "ABC123",
+        }
+        validation = {"can_import": False, "existing_device": existing_device}
         selections = {}
 
         request = self._create_request("link", 42, use_sysname=True)
 
         with (
             patch.object(DeviceConflictActionView, "get_validated_device_with_selections") as mock_validate,
+            patch.object(DeviceConflictActionView, "render_device_row") as mock_render,
             patch("dcim.models.Device") as mock_device_cls,
+            patch("netbox_librenms_plugin.views.imports.actions.transaction") as mock_tx,
         ):
+            mock_tx.atomic.return_value = MagicMock()
             mock_device_cls.objects.get.return_value = existing_device
+            mock_device_cls.objects.select_for_update.return_value.get.return_value = existing_device
+            mock_device_cls.objects.filter.return_value.first.return_value = None
+            mock_device_cls.objects.filter.return_value.exclude.return_value.first.return_value = None
+            mock_device_cls.objects.filter.return_value.exclude.return_value.exists.return_value = False
             mock_validate.return_value = (libre_device, validation, selections)
+            mock_render.return_value = MagicMock()
 
-            response = view.post(request, device_id=10)
+            view.request = request
+            view.post(request, device_id=10)
 
-        assert response.status_code == 400
-        existing_device.save.assert_not_called()
+        assert existing_device.custom_field_data["librenms_id"] == {"production": 10}
 
     @patch("netbox_librenms_plugin.views.imports.actions.cache")
     @patch("netbox_librenms_plugin.views.imports.actions.get_import_device_cache_key")
-    def test_device_type_mismatch_allowed_with_force(self, mock_cache_key, mock_cache):
-        """Action should proceed when device_type_mismatch is True and force is set."""
+    def test_update_action_sets_hostname_serial_and_librenms_id(self, mock_cache_key, mock_cache):
+        """Update action should set hostname, serial, and librenms_id."""
         from netbox_librenms_plugin.views.imports.actions import DeviceConflictActionView
 
         view = self._create_view()
@@ -2384,320 +2679,688 @@ def test_device_type_mismatch_allowed_with_force(self, mock_cache_key, mock_cach
         existing_device.pk = 42
         existing_device.custom_field_data = {}
         existing_device.name = "old-name"
+        existing_device.serial = "OLD-SERIAL"
 
         libre_device = {
             "device_id": 10,
-            "hostname": "switch-01",
-            "sysName": "switch-01.example.com",
-            "serial": "ABC123",
+            "hostname": "84.116.251.35",
+            "sysName": "new-name.example.com",
+            "serial": "NEW-SERIAL",
         }
-        validation = {"can_import": False, "device_type_mismatch": True, "existing_device": existing_device}
+        validation = {"can_import": False, "existing_device": existing_device}
         selections = {}
 
-        request = self._create_request("link", 42, use_sysname=True)
-        request.POST["force"] = "on"
+        request = self._create_request("update", 42, use_sysname=True)
 
         with (
             patch.object(DeviceConflictActionView, "get_validated_device_with_selections") as mock_validate,
             patch.object(DeviceConflictActionView, "render_device_row") as mock_render,
             patch("dcim.models.Device") as mock_device_cls,
+            patch("netbox_librenms_plugin.views.imports.actions.transaction") as mock_tx,
         ):
+            mock_tx.atomic.return_value = MagicMock()
             mock_device_cls.objects.get.return_value = existing_device
+            mock_device_cls.objects.select_for_update.return_value.get.return_value = existing_device
+            mock_device_cls.objects.select_for_update.return_value.filter.return_value.exclude.return_value.first.return_value = None
+            mock_device_cls.objects.filter.return_value.first.return_value = None
             mock_device_cls.objects.filter.return_value.exclude.return_value.first.return_value = None
+            mock_device_cls.objects.filter.return_value.exclude.return_value.exists.return_value = False
             mock_validate.return_value = (libre_device, validation, selections)
             mock_render.return_value = MagicMock()
 
+            view.request = request
             view.post(request, device_id=10)
 
-        assert existing_device.custom_field_data["librenms_id"] == 10
+        assert existing_device.custom_field_data["librenms_id"] == {"default": 10}
+        assert existing_device.serial == "NEW-SERIAL"
+        assert existing_device.name == "new-name.example.com"
         existing_device.save.assert_called_once()
 
     @patch("netbox_librenms_plugin.views.imports.actions.cache")
     @patch("netbox_librenms_plugin.views.imports.actions.get_import_device_cache_key")
-    def test_force_with_mismatch_updates_device_type(self, mock_cache_key, mock_cache):
-        """Force with device_type_mismatch should update existing device's device_type."""
+    def test_update_action_uses_non_default_server_key(self, mock_cache_key, mock_cache):
+        """Update action should store librenms_id under the active server key."""
         from netbox_librenms_plugin.views.imports.actions import DeviceConflictActionView
 
         view = self._create_view()
+        view._librenms_api = MagicMock()
+        view._librenms_api.server_key = "production"
         existing_device = MagicMock()
         existing_device.pk = 42
         existing_device.custom_field_data = {}
         existing_device.name = "old-name"
+        existing_device.serial = "OLD-SERIAL"
 
-        librenms_device_type = MagicMock()
-        librenms_device_type.pk = 99
         libre_device = {
             "device_id": 10,
             "hostname": "switch-01",
-            "sysName": "switch-01.example.com",
-            "serial": "ABC123",
-        }
-        validation = {
-            "can_import": False,
-            "device_type_mismatch": True,
-            "device_type": {"device_type": librenms_device_type},
-            "existing_device": existing_device,
+            "sysName": "switch-01",
+            "serial": "NEW-SERIAL",
+            "resolved_name": "switch-01",
         }
+        validation = {"can_import": False, "existing_device": existing_device, "resolved_name": "switch-01"}
         selections = {}
 
-        request = self._create_request("link", 42, use_sysname=True)
-        request.POST["force"] = "on"
+        request = self._create_request("update", 42)
 
         with (
             patch.object(DeviceConflictActionView, "get_validated_device_with_selections") as mock_validate,
             patch.object(DeviceConflictActionView, "render_device_row") as mock_render,
             patch("dcim.models.Device") as mock_device_cls,
+            patch("netbox_librenms_plugin.views.imports.actions.transaction") as mock_tx,
         ):
+            mock_tx.atomic.return_value = MagicMock()
             mock_device_cls.objects.get.return_value = existing_device
+            mock_device_cls.objects.select_for_update.return_value.get.return_value = existing_device
+            mock_device_cls.objects.select_for_update.return_value.filter.return_value.exclude.return_value.first.return_value = None
+            mock_device_cls.objects.filter.return_value.first.return_value = None
             mock_device_cls.objects.filter.return_value.exclude.return_value.first.return_value = None
+            mock_device_cls.objects.filter.return_value.exclude.return_value.exists.return_value = False
             mock_validate.return_value = (libre_device, validation, selections)
             mock_render.return_value = MagicMock()
 
+            view.request = request
             view.post(request, device_id=10)
 
-        assert existing_device.device_type == librenms_device_type
-        assert existing_device.custom_field_data["librenms_id"] == 10
-        existing_device.save.assert_called_once()
+        assert existing_device.custom_field_data["librenms_id"] == {"production": 10}
 
     @patch("netbox_librenms_plugin.views.imports.actions.cache")
     @patch("netbox_librenms_plugin.views.imports.actions.get_import_device_cache_key")
-    def test_update_type_action_changes_device_type(self, mock_cache_key, mock_cache):
-        """update_type action should change device type on existing device."""
+    def test_update_serial_action_updates_serial_only(self, mock_cache_key, mock_cache):
+        """Update serial action should update serial and librenms_id but not hostname."""
         from netbox_librenms_plugin.views.imports.actions import DeviceConflictActionView
 
         view = self._create_view()
         existing_device = MagicMock()
         existing_device.pk = 42
-        existing_device.custom_field_data = {"librenms_id": 10}
+        existing_device.custom_field_data = {}
         existing_device.name = "switch-01"
-        old_device_type = MagicMock()
-        existing_device.device_type = old_device_type
+        existing_device.serial = "OLD-SERIAL"
 
-        new_device_type = MagicMock()
-        new_device_type.pk = 99
-        libre_device = {
-            "device_id": 10,
-            "hostname": "switch-01",
-            "serial": "ABC123",
-        }
-        validation = {
-            "can_import": False,
-            "device_type_mismatch": True,
-            "device_type": {"device_type": new_device_type},
-            "existing_device": existing_device,
-        }
+        libre_device = {"device_id": 10, "hostname": "switch-01", "serial": "NEW-SERIAL"}
+        validation = {"can_import": False, "existing_device": existing_device}
         selections = {}
 
-        request = self._create_request("update_type", 42)
-        request.POST["force"] = "on"
+        request = self._create_request("update_serial", 42)
 
         with (
             patch.object(DeviceConflictActionView, "get_validated_device_with_selections") as mock_validate,
             patch.object(DeviceConflictActionView, "render_device_row") as mock_render,
             patch("dcim.models.Device") as mock_device_cls,
+            patch("netbox_librenms_plugin.views.imports.actions.transaction") as mock_tx,
         ):
+            mock_tx.atomic.return_value = MagicMock()
             mock_device_cls.objects.get.return_value = existing_device
+            mock_device_cls.objects.select_for_update.return_value.get.return_value = existing_device
+            mock_device_cls.objects.select_for_update.return_value.filter.return_value.exclude.return_value.first.return_value = None
+            mock_device_cls.objects.filter.return_value.first.return_value = None
+            mock_device_cls.objects.filter.return_value.exclude.return_value.first.return_value = None
+            mock_device_cls.objects.filter.return_value.exclude.return_value.exists.return_value = False
             mock_validate.return_value = (libre_device, validation, selections)
             mock_render.return_value = MagicMock()
 
+            view.request = request
             view.post(request, device_id=10)
 
-        assert existing_device.device_type == new_device_type
+        assert existing_device.custom_field_data["librenms_id"] == {"default": 10}
+        assert existing_device.serial == "NEW-SERIAL"
+        # Name should NOT be changed by update_serial
+        assert existing_device.name == "switch-01"
         existing_device.save.assert_called_once()
 
     @patch("netbox_librenms_plugin.views.imports.actions.cache")
     @patch("netbox_librenms_plugin.views.imports.actions.get_import_device_cache_key")
-    def test_sync_serial_action(self, mock_cache_key, mock_cache):
-        """sync_serial action should update serial from LibreNMS."""
-        from netbox_librenms_plugin.views.imports.actions import DeviceConflictActionView
+    def test_update_skips_dash_serial(self, mock_cache_key, mock_cache):
+        """Update should not set serial to '-' (LibreNMS placeholder)."""
+        from netbox_librenms_plugin.views.imports.actions import DeviceConflictActionView
 
         view = self._create_view()
         existing_device = MagicMock()
-        existing_device.serial = "OLD123"
-        libre_device = {"device_id": 10, "serial": "NEW456", "sysName": "test"}
-        validation = {"existing_device": existing_device, "device_type_mismatch": False}
+        existing_device.pk = 42
+        existing_device.custom_field_data = {}
+        existing_device.name = "switch-01"
+        existing_device.serial = "EXISTING"
+
+        libre_device = {"device_id": 10, "hostname": "switch-01", "serial": "-"}
+        validation = {"can_import": False, "existing_device": existing_device}
         selections = {}
 
-        request = self._create_request("sync_serial", 42)
+        request = self._create_request("update_serial", 42)
 
         with (
             patch.object(DeviceConflictActionView, "get_validated_device_with_selections") as mock_validate,
             patch.object(DeviceConflictActionView, "render_device_row") as mock_render,
             patch("dcim.models.Device") as mock_device_cls,
+            patch("netbox_librenms_plugin.views.imports.actions.transaction") as mock_tx,
         ):
+            mock_tx.atomic.return_value = MagicMock()
             mock_device_cls.objects.get.return_value = existing_device
-            mock_device_cls.objects.filter.return_value.exclude.return_value.first.return_value = None
+            mock_device_cls.objects.select_for_update.return_value.get.return_value = existing_device
+            mock_device_cls.objects.select_for_update.return_value.filter.return_value.exclude.return_value.first.return_value = None
+            mock_device_cls.objects.filter.return_value.exclude.return_value.exists.return_value = False
             mock_validate.return_value = (libre_device, validation, selections)
             mock_render.return_value = MagicMock()
 
+            view.request = request
             view.post(request, device_id=10)
 
-        assert existing_device.serial == "NEW456"
-        existing_device.save.assert_called_once()
+        # Serial should NOT be updated to '-'
+        assert existing_device.serial == "EXISTING"
 
-    @patch("netbox_librenms_plugin.views.imports.actions.cache")
-    @patch("netbox_librenms_plugin.views.imports.actions.get_import_device_cache_key")
-    def test_sync_platform_action(self, mock_cache_key, mock_cache):
-        """sync_platform action should update platform from LibreNMS OS."""
+    def test_missing_action_returns_400(self):
+        """Missing action or existing_device_id should return 400."""
+        view = self._create_view()
+        request = MagicMock()
+        request.user.has_perm.return_value = True
+        request.POST = {}
+
+        view.request = request
+        response = view.post(request, device_id=10)
+        assert response.status_code == 400
+
+    def test_unknown_action_returns_400(self):
+        """Unknown action should return 400."""
         from netbox_librenms_plugin.views.imports.actions import DeviceConflictActionView
 
         view = self._create_view()
-        existing_device = MagicMock()
-        existing_device.platform = None
-        libre_device = {"device_id": 10, "os": "ios", "sysName": "test"}
-        validation = {"existing_device": existing_device, "device_type_mismatch": False}
-        selections = {}
+        request = self._create_request("invalid_action", 42)
 
-        mock_platform = MagicMock()
-        request = self._create_request("sync_platform", 42)
+        existing_device = MagicMock()
+        existing_device.pk = 42
+        libre_device = {"device_id": 10, "hostname": "switch-01", "serial": "ABC"}
 
         with (
             patch.object(DeviceConflictActionView, "get_validated_device_with_selections") as mock_validate,
-            patch.object(DeviceConflictActionView, "render_device_row") as mock_render,
+            patch.object(DeviceConflictActionView, "require_object_permissions", return_value=None),
             patch("dcim.models.Device") as mock_device_cls,
-            patch("dcim.models.Platform") as mock_platform_cls,
         ):
             mock_device_cls.objects.get.return_value = existing_device
-            mock_platform_cls.objects.get.return_value = mock_platform
-            mock_validate.return_value = (libre_device, validation, selections)
-            mock_render.return_value = MagicMock()
+            mock_device_cls.objects.select_for_update.return_value.get.return_value = existing_device
+            mock_device_cls.objects.select_for_update.return_value.filter.return_value.exclude.return_value.first.return_value = None
+            # Include existing_device so the validated-conflict-target guard passes;
+            # we want to exercise the unknown-action branch, not the missing-device guard.
+            mock_validate.return_value = (libre_device, {"existing_device": existing_device}, {})
 
-            view.post(request, device_id=10)
+            view.request = request
+            response = view.post(request, device_id=10)
 
-        assert existing_device.platform == mock_platform
-        existing_device.save.assert_called_once()
+        assert response.status_code == 400
 
     @patch("netbox_librenms_plugin.views.imports.actions.cache")
     @patch("netbox_librenms_plugin.views.imports.actions.get_import_device_cache_key")
-    def test_sync_device_type_action(self, mock_cache_key, mock_cache):
-        """sync_device_type action should update device type from LibreNMS hardware match."""
+    def test_sync_name_action_updates_name(self, mock_cache_key, mock_cache):
+        """Sync name action should update device name using sysName."""
         from netbox_librenms_plugin.views.imports.actions import DeviceConflictActionView
 
         view = self._create_view()
         existing_device = MagicMock()
-        new_device_type = MagicMock()
-        libre_device = {"device_id": 10, "hardware": "Catalyst C4900M", "sysName": "test"}
-        validation = {"existing_device": existing_device, "device_type_mismatch": False}
+        existing_device.pk = 42
+        existing_device.custom_field_data = {"librenms_id": 10}
+        existing_device.name = "84.116.251.35"
+
+        libre_device = {
+            "device_id": 10,
+            "hostname": "84.116.251.35",
+            "sysName": "switch-01.example.com",
+            "serial": "ABC123",
+        }
+        validation = {"can_import": False, "existing_device": existing_device}
         selections = {}
 
-        request = self._create_request("sync_device_type", 42)
+        request = self._create_request("sync_name", 42, use_sysname=True)
 
         with (
             patch.object(DeviceConflictActionView, "get_validated_device_with_selections") as mock_validate,
             patch.object(DeviceConflictActionView, "render_device_row") as mock_render,
             patch("dcim.models.Device") as mock_device_cls,
-            patch("netbox_librenms_plugin.utils.match_librenms_hardware_to_device_type") as mock_hw_match,
         ):
             mock_device_cls.objects.get.return_value = existing_device
-            mock_hw_match.return_value = {"matched": True, "device_type": new_device_type}
+            mock_device_cls.objects.select_for_update.return_value.get.return_value = existing_device
+            mock_device_cls.objects.select_for_update.return_value.filter.return_value.exclude.return_value.first.return_value = None
             mock_validate.return_value = (libre_device, validation, selections)
             mock_render.return_value = MagicMock()
 
+            view.request = request
             view.post(request, device_id=10)
 
-        assert existing_device.device_type == new_device_type
+        assert existing_device.name == "switch-01.example.com"
         existing_device.save.assert_called_once()
+        assert existing_device.custom_field_data["librenms_id"] == 10
 
+    @patch("netbox_librenms_plugin.views.imports.actions.cache")
+    @patch("netbox_librenms_plugin.views.imports.actions.get_import_device_cache_key")
+    def test_device_type_mismatch_blocked_without_force(self, mock_cache_key, mock_cache):
+        """Action should be blocked when device_type_mismatch is True and force is not set."""
+        from netbox_librenms_plugin.views.imports.actions import DeviceConflictActionView
 
-class TestBuildSyncInfo:
-    """Test DeviceValidationDetailsView._build_sync_info method."""
-
-    def test_all_synced(self):
-        """When serial, platform, device type all match, all_synced is True."""
-        from netbox_librenms_plugin.views.imports.actions import DeviceValidationDetailsView
+        view = self._create_view()
+        existing_device = MagicMock()
+        existing_device.pk = 42
+        existing_device.custom_field_data = {}
 
-        existing = MagicMock()
-        existing.serial = "ABC123"
-        platform = MagicMock()
-        platform.pk = 1
-        existing.platform = platform
-        device_type = MagicMock()
-        device_type.pk = 5
-        existing.device_type = device_type
+        libre_device = {"device_id": 10, "hostname": "switch-01", "serial": "ABC123"}
+        validation = {"can_import": False, "device_type_mismatch": True, "existing_device": existing_device}
+        selections = {}
 
-        libre_device = {"serial": "ABC123", "os": "ios", "hardware": "Catalyst C4900M"}
+        request = self._create_request("link", 42, use_sysname=True)
 
         with (
-            patch("netbox_librenms_plugin.utils.find_matching_platform") as mock_platform_match,
-            patch("netbox_librenms_plugin.utils.match_librenms_hardware_to_device_type") as mock_hw_match,
+            patch.object(DeviceConflictActionView, "get_validated_device_with_selections") as mock_validate,
+            patch("dcim.models.Device") as mock_device_cls,
         ):
-            mock_platform_match.return_value = {"found": True, "platform": platform}
-            mock_hw_match.return_value = {"matched": True, "device_type": device_type}
-
-            result = DeviceValidationDetailsView._build_sync_info(libre_device, existing)
-
-        assert result["all_synced"] is True
-        assert result["serial_synced"] is True
-        assert result["platform_synced"] is True
-        assert result["device_type_synced"] is True
-
-    def test_serial_out_of_sync(self):
-        """When serial differs, serial_synced is False."""
-        from netbox_librenms_plugin.views.imports.actions import DeviceValidationDetailsView
+            mock_device_cls.objects.get.return_value = existing_device
+            mock_device_cls.objects.select_for_update.return_value.get.return_value = existing_device
+            mock_device_cls.objects.select_for_update.return_value.filter.return_value.exclude.return_value.first.return_value = None
+            mock_validate.return_value = (libre_device, validation, selections)
 
-        existing = MagicMock()
-        existing.serial = "OLD123"
-        existing.platform = None
-        device_type = MagicMock()
-        device_type.pk = 5
-        existing.device_type = device_type
+            view.request = request
+            response = view.post(request, device_id=10)
 
-        libre_device = {"serial": "NEW456", "os": "-", "hardware": "-"}
+        assert response.status_code == 400
+        existing_device.save.assert_not_called()
 
-        result = DeviceValidationDetailsView._build_sync_info(libre_device, existing)
+    @patch("netbox_librenms_plugin.views.imports.actions.cache")
+    @patch("netbox_librenms_plugin.views.imports.actions.get_import_device_cache_key")
+    def test_device_type_mismatch_allowed_with_force(self, mock_cache_key, mock_cache):
+        """Action should proceed when device_type_mismatch is True and force is set."""
+        from netbox_librenms_plugin.views.imports.actions import DeviceConflictActionView
 
-        assert result["serial_synced"] is False
-        assert result["all_synced"] is False
+        view = self._create_view()
+        existing_device = MagicMock()
+        existing_device.pk = 42
+        existing_device.custom_field_data = {}
+        existing_device.name = "old-name"
 
-    def test_platform_out_of_sync(self):
-        """When platform differs, platform_synced is False."""
-        from netbox_librenms_plugin.views.imports.actions import DeviceValidationDetailsView
+        libre_device = {
+            "device_id": 10,
+            "hostname": "switch-01",
+            "sysName": "switch-01.example.com",
+            "serial": "ABC123",
+        }
+        validation = {"can_import": False, "device_type_mismatch": True, "existing_device": existing_device}
+        selections = {}
 
-        existing = MagicMock()
-        existing.serial = "ABC123"
-        old_platform = MagicMock()
-        old_platform.pk = 1
-        existing.platform = old_platform
-        device_type = MagicMock()
-        device_type.pk = 5
-        existing.device_type = device_type
+        request = self._create_request("link", 42, use_sysname=True)
+        request.POST["force"] = "on"
 
-        new_platform = MagicMock()
-        new_platform.pk = 2
+        with (
+            patch.object(DeviceConflictActionView, "get_validated_device_with_selections") as mock_validate,
+            patch.object(DeviceConflictActionView, "render_device_row") as mock_render,
+            patch("dcim.models.Device") as mock_device_cls,
+            patch("netbox_librenms_plugin.views.imports.actions.transaction") as mock_tx,
+        ):
+            mock_tx.atomic.return_value = MagicMock()
+            mock_device_cls.objects.get.return_value = existing_device
+            mock_device_cls.objects.select_for_update.return_value.get.return_value = existing_device
+            mock_device_cls.objects.select_for_update.return_value.filter.return_value.exclude.return_value.first.return_value = None
+            mock_device_cls.objects.filter.return_value.first.return_value = None
+            mock_device_cls.objects.filter.return_value.exclude.return_value.first.return_value = None
+            mock_device_cls.objects.filter.return_value.exclude.return_value.exists.return_value = False
+            mock_validate.return_value = (libre_device, validation, selections)
+            mock_render.return_value = MagicMock()
 
-        libre_device = {"serial": "ABC123", "os": "junos", "hardware": "-"}
+            view.request = request
+            view.post(request, device_id=10)
 
-        with patch("netbox_librenms_plugin.utils.find_matching_platform") as mock_platform_match:
-            mock_platform_match.return_value = {"found": True, "platform": new_platform}
+        assert existing_device.custom_field_data["librenms_id"] == {"default": 10}
+        existing_device.save.assert_called_once()
 
-            result = DeviceValidationDetailsView._build_sync_info(libre_device, existing)
+    @patch("netbox_librenms_plugin.views.imports.actions.cache")
+    @patch("netbox_librenms_plugin.views.imports.actions.get_import_device_cache_key")
+    def test_force_with_mismatch_updates_device_type(self, mock_cache_key, mock_cache):
+        """Force with device_type_mismatch should update existing device's device_type."""
+        from netbox_librenms_plugin.views.imports.actions import DeviceConflictActionView
 
-        assert result["platform_synced"] is False
-        assert result["all_synced"] is False
+        view = self._create_view()
+        existing_device = MagicMock()
+        existing_device.pk = 42
+        existing_device.custom_field_data = {}
+        existing_device.name = "old-name"
 
-    def test_hardware_no_match_device_type_out_of_sync(self):
-        """When hardware is present but no device type match found, device_type_synced is False."""
-        from netbox_librenms_plugin.views.imports.actions import DeviceValidationDetailsView
+        librenms_device_type = MagicMock()
+        librenms_device_type.pk = 99
+        libre_device = {
+            "device_id": 10,
+            "hostname": "switch-01",
+            "sysName": "switch-01.example.com",
+            "serial": "ABC123",
+        }
+        validation = {
+            "can_import": False,
+            "device_type_mismatch": True,
+            "device_type": {"device_type": librenms_device_type},
+            "existing_device": existing_device,
+        }
+        selections = {}
 
-        existing = MagicMock()
-        existing.serial = "ABC123"
-        existing.platform = None
-        device_type = MagicMock()
-        device_type.pk = 5
-        existing.device_type = device_type
+        request = self._create_request("link", 42, use_sysname=True)
+        request.POST["force"] = "on"
 
-        libre_device = {"serial": "ABC123", "os": "-", "hardware": "UnknownHardwareXYZ"}
+        with (
+            patch.object(DeviceConflictActionView, "get_validated_device_with_selections") as mock_validate,
+            patch.object(DeviceConflictActionView, "render_device_row") as mock_render,
+            patch("dcim.models.Device") as mock_device_cls,
+            patch("netbox_librenms_plugin.views.imports.actions.transaction") as mock_tx,
+        ):
+            mock_tx.atomic.return_value = MagicMock()
+            mock_device_cls.objects.get.return_value = existing_device
+            mock_device_cls.objects.select_for_update.return_value.get.return_value = existing_device
+            mock_device_cls.objects.select_for_update.return_value.filter.return_value.exclude.return_value.first.return_value = None
+            mock_device_cls.objects.filter.return_value.first.return_value = None
+            mock_device_cls.objects.filter.return_value.exclude.return_value.first.return_value = None
+            mock_device_cls.objects.filter.return_value.exclude.return_value.exists.return_value = False
+            mock_validate.return_value = (libre_device, validation, selections)
+            mock_render.return_value = MagicMock()
 
-        with patch("netbox_librenms_plugin.utils.match_librenms_hardware_to_device_type") as mock_hw_match:
-            mock_hw_match.return_value = {"matched": False, "device_type": None}
+            view.request = request
+            view.post(request, device_id=10)
 
-            result = DeviceValidationDetailsView._build_sync_info(libre_device, existing)
+        assert existing_device.device_type == librenms_device_type
+        assert existing_device.custom_field_data["librenms_id"] == {"default": 10}
+        existing_device.save.assert_called_once()
 
-        assert result["device_type_synced"] is False
-        assert result["all_synced"] is False
+    @patch("netbox_librenms_plugin.views.imports.actions.cache")
+    @patch("netbox_librenms_plugin.views.imports.actions.get_import_device_cache_key")
+    def test_update_type_action_changes_device_type(self, mock_cache_key, mock_cache):
+        """update_type action should change device type on existing device."""
+        from netbox_librenms_plugin.views.imports.actions import DeviceConflictActionView
 
+        view = self._create_view()
+        existing_device = MagicMock()
+        existing_device.pk = 42
+        existing_device.custom_field_data = {"librenms_id": 10}
+        existing_device.name = "switch-01"
+        old_device_type = MagicMock()
+        existing_device.device_type = old_device_type
 
-class TestImportSingleDeviceLazyValidation:
+        new_device_type = MagicMock()
+        new_device_type.pk = 99
+        libre_device = {
+            "device_id": 10,
+            "hostname": "switch-01",
+            "serial": "ABC123",
+        }
+        validation = {
+            "can_import": False,
+            "device_type_mismatch": True,
+            "device_type": {"device_type": new_device_type},
+            "existing_device": existing_device,
+        }
+        selections = {}
+
+        request = self._create_request("update_type", 42)
+        request.POST["force"] = "on"
+
+        with (
+            patch.object(DeviceConflictActionView, "get_validated_device_with_selections") as mock_validate,
+            patch.object(DeviceConflictActionView, "render_device_row") as mock_render,
+            patch("dcim.models.Device") as mock_device_cls,
+        ):
+            mock_device_cls.objects.get.return_value = existing_device
+            mock_device_cls.objects.select_for_update.return_value.get.return_value = existing_device
+            mock_device_cls.objects.select_for_update.return_value.filter.return_value.exclude.return_value.first.return_value = None
+            mock_validate.return_value = (libre_device, validation, selections)
+            mock_render.return_value = MagicMock()
+
+            view.request = request
+            view.post(request, device_id=10)
+
+        assert existing_device.device_type == new_device_type
+        existing_device.save.assert_called_once()
+        assert existing_device.custom_field_data["librenms_id"] == 10
+
+    @patch("netbox_librenms_plugin.views.imports.actions.cache")
+    @patch("netbox_librenms_plugin.views.imports.actions.get_import_device_cache_key")
+    def test_sync_serial_action(self, mock_cache_key, mock_cache):
+        """sync_serial action should update serial from LibreNMS."""
+        from netbox_librenms_plugin.views.imports.actions import DeviceConflictActionView
+
+        view = self._create_view()
+        existing_device = MagicMock()
+        existing_device.serial = "OLD123"
+        libre_device = {"device_id": 10, "serial": "NEW456", "sysName": "test"}
+        validation = {"existing_device": existing_device, "device_type_mismatch": False}
+        selections = {}
+
+        request = self._create_request("sync_serial", 42)
+
+        with (
+            patch.object(DeviceConflictActionView, "get_validated_device_with_selections") as mock_validate,
+            patch.object(DeviceConflictActionView, "render_device_row") as mock_render,
+            patch("dcim.models.Device") as mock_device_cls,
+            patch("netbox_librenms_plugin.views.imports.actions.transaction") as mock_tx,
+        ):
+            mock_tx.atomic.return_value = MagicMock()
+            mock_device_cls.objects.get.return_value = existing_device
+            mock_device_cls.objects.select_for_update.return_value.get.return_value = existing_device
+            mock_device_cls.objects.select_for_update.return_value.filter.return_value.exclude.return_value.first.return_value = None
+            mock_device_cls.objects.filter.return_value.first.return_value = None
+            mock_device_cls.objects.filter.return_value.exclude.return_value.first.return_value = None
+            mock_device_cls.objects.filter.return_value.exclude.return_value.exists.return_value = False
+            mock_validate.return_value = (libre_device, validation, selections)
+            mock_render.return_value = MagicMock()
+
+            view.request = request
+            view.post(request, device_id=10)
+
+        assert existing_device.serial == "NEW456"
+        existing_device.save.assert_called_once()
+
+    @patch("netbox_librenms_plugin.views.imports.actions.cache")
+    @patch("netbox_librenms_plugin.views.imports.actions.get_import_device_cache_key")
+    def test_sync_platform_action(self, mock_cache_key, mock_cache):
+        """sync_platform action should update platform from LibreNMS OS."""
+        from netbox_librenms_plugin.views.imports.actions import DeviceConflictActionView
+
+        view = self._create_view()
+        existing_device = MagicMock()
+        existing_device.platform = None
+        libre_device = {"device_id": 10, "os": "ios", "sysName": "test"}
+        validation = {"existing_device": existing_device, "device_type_mismatch": False}
+        selections = {}
+
+        mock_platform = MagicMock()
+        request = self._create_request("sync_platform", 42)
+
+        with (
+            patch.object(DeviceConflictActionView, "get_validated_device_with_selections") as mock_validate,
+            patch.object(DeviceConflictActionView, "render_device_row") as mock_render,
+            patch("dcim.models.Device") as mock_device_cls,
+            # Patch find_matching_platform at the utility module level — the action imports
+            # it from netbox_librenms_plugin.utils, so that is the correct seam to mock.
+            patch("netbox_librenms_plugin.utils.find_matching_platform") as mock_find_platform,
+        ):
+            mock_device_cls.objects.get.return_value = existing_device
+            mock_device_cls.objects.select_for_update.return_value.get.return_value = existing_device
+            mock_device_cls.objects.select_for_update.return_value.filter.return_value.exclude.return_value.first.return_value = None
+            mock_find_platform.return_value = {"found": True, "platform": mock_platform, "match_type": "exact"}
+            mock_validate.return_value = (libre_device, validation, selections)
+            mock_render.return_value = MagicMock()
+
+            view.request = request
+            view.post(request, device_id=10)
+
+        assert existing_device.platform == mock_platform
+        existing_device.save.assert_called_once()
+
+    @patch("netbox_librenms_plugin.views.imports.actions.cache")
+    @patch("netbox_librenms_plugin.views.imports.actions.get_import_device_cache_key")
+    def test_sync_device_type_action(self, mock_cache_key, mock_cache):
+        """sync_device_type action should update device type from LibreNMS hardware match."""
+        from netbox_librenms_plugin.views.imports.actions import DeviceConflictActionView
+
+        view = self._create_view()
+        existing_device = MagicMock()
+        new_device_type = MagicMock()
+        libre_device = {"device_id": 10, "hardware": "Catalyst C4900M", "sysName": "test"}
+        validation = {"existing_device": existing_device, "device_type_mismatch": False}
+        selections = {}
+
+        request = self._create_request("sync_device_type", 42)
+
+        with (
+            patch.object(DeviceConflictActionView, "get_validated_device_with_selections") as mock_validate,
+            patch.object(DeviceConflictActionView, "render_device_row") as mock_render,
+            patch("dcim.models.Device") as mock_device_cls,
+            patch("netbox_librenms_plugin.utils.match_librenms_hardware_to_device_type") as mock_hw_match,
+        ):
+            mock_device_cls.objects.get.return_value = existing_device
+            mock_device_cls.objects.select_for_update.return_value.get.return_value = existing_device
+            mock_device_cls.objects.select_for_update.return_value.filter.return_value.exclude.return_value.first.return_value = None
+            mock_hw_match.return_value = {"matched": True, "device_type": new_device_type}
+            mock_validate.return_value = (libre_device, validation, selections)
+            mock_render.return_value = MagicMock()
+
+            view.request = request
+            view.post(request, device_id=10)
+
+        assert existing_device.device_type == new_device_type
+        existing_device.save.assert_called_once()
+
+
+class TestBuildSyncInfo:
+    """Test DeviceValidationDetailsView._build_sync_info method."""
+
+    def test_all_synced(self):
+        """When serial, platform, device type all match, all_synced is True."""
+        from netbox_librenms_plugin.views.imports.actions import DeviceValidationDetailsView
+
+        existing = MagicMock()
+        existing.serial = "ABC123"
+        platform = MagicMock()
+        platform.pk = 1
+        existing.platform = platform
+        device_type = MagicMock()
+        device_type.pk = 5
+        existing.device_type = device_type
+
+        libre_device = {"serial": "ABC123", "os": "ios", "hardware": "Catalyst C4900M"}
+
+        with (
+            patch("netbox_librenms_plugin.utils.find_matching_platform") as mock_platform_match,
+            patch("netbox_librenms_plugin.utils.match_librenms_hardware_to_device_type") as mock_hw_match,
+        ):
+            mock_platform_match.return_value = {"found": True, "platform": platform}
+            mock_hw_match.return_value = {"matched": True, "device_type": device_type}
+
+            result = DeviceValidationDetailsView._build_sync_info(libre_device, existing)
+
+        assert result["all_synced"] is True
+        assert result["serial_synced"] is True
+        assert result["platform_synced"] is True
+        assert result["device_type_synced"] is True
+
+    def test_serial_out_of_sync(self):
+        """When serial differs, serial_synced is False."""
+        from netbox_librenms_plugin.views.imports.actions import DeviceValidationDetailsView
+
+        existing = MagicMock()
+        existing.serial = "OLD123"
+        existing.platform = None
+        device_type = MagicMock()
+        device_type.pk = 5
+        existing.device_type = device_type
+
+        libre_device = {"serial": "NEW456", "os": "-", "hardware": "-"}
+
+        result = DeviceValidationDetailsView._build_sync_info(libre_device, existing)
+
+        assert result["serial_synced"] is False
+        assert result["all_synced"] is False
+
+    def test_platform_out_of_sync(self):
+        """When platform differs, platform_synced is False."""
+        from netbox_librenms_plugin.views.imports.actions import DeviceValidationDetailsView
+
+        existing = MagicMock()
+        existing.serial = "ABC123"
+        old_platform = MagicMock()
+        old_platform.pk = 1
+        existing.platform = old_platform
+        device_type = MagicMock()
+        device_type.pk = 5
+        existing.device_type = device_type
+
+        new_platform = MagicMock()
+        new_platform.pk = 2
+
+        libre_device = {"serial": "ABC123", "os": "junos", "hardware": "-"}
+
+        with patch("netbox_librenms_plugin.utils.find_matching_platform") as mock_platform_match:
+            mock_platform_match.return_value = {"found": True, "platform": new_platform}
+
+            result = DeviceValidationDetailsView._build_sync_info(libre_device, existing)
+
+        assert result["platform_synced"] is False
+        assert result["all_synced"] is False
+
+    def test_platform_no_match_found_returns_bool(self):
+        """When find_matching_platform returns no match, platform_synced must be False (not None)."""
+        from netbox_librenms_plugin.views.imports.actions import DeviceValidationDetailsView
+
+        existing = MagicMock()
+        existing.serial = "ABC123"
+        existing.platform = MagicMock()  # device has a platform set
+        device_type = MagicMock()
+        device_type.pk = 5
+        existing.device_type = device_type
+
+        libre_device = {"serial": "ABC123", "os": "ios", "hardware": "-"}
+
+        with patch("netbox_librenms_plugin.utils.find_matching_platform") as mock_platform_match:
+            mock_platform_match.return_value = {"found": False, "platform": None}
+
+            result = DeviceValidationDetailsView._build_sync_info(libre_device, existing)
+
+        # Without bool() cast this would be None; verify it's exactly False (type-stable)
+        assert result["platform_synced"] is False
+        assert isinstance(result["platform_synced"], bool)
+
+    def test_platform_synced_no_netbox_platform_returns_bool(self):
+        """When device has no platform in NetBox and os is non-dash, platform_synced must be bool."""
+        from netbox_librenms_plugin.views.imports.actions import DeviceValidationDetailsView
+
+        existing = MagicMock()
+        existing.serial = "ABC123"
+        existing.platform = None  # no platform on device
+        device_type = MagicMock()
+        device_type.pk = 5
+        existing.device_type = device_type
+
+        libre_device = {"serial": "ABC123", "os": "eos", "hardware": "-"}
+
+        with patch("netbox_librenms_plugin.utils.find_matching_platform") as mock_platform_match:
+            mock_platform_match.return_value = {"found": True, "platform": MagicMock()}
+
+            result = DeviceValidationDetailsView._build_sync_info(libre_device, existing)
+
+        # None and ... returns None; bool() cast ensures False
+        assert result["platform_synced"] is False
+        assert isinstance(result["platform_synced"], bool)
+
+    def test_hardware_no_match_device_type_out_of_sync(self):
+        """When hardware is present but no device type match found, device_type_synced is False."""
+        from netbox_librenms_plugin.views.imports.actions import DeviceValidationDetailsView
+
+        existing = MagicMock()
+        existing.serial = "ABC123"
+        existing.platform = None
+        device_type = MagicMock()
+        device_type.pk = 5
+        existing.device_type = device_type
+
+        libre_device = {"serial": "ABC123", "os": "-", "hardware": "UnknownHardwareXYZ"}
+
+        with patch("netbox_librenms_plugin.utils.match_librenms_hardware_to_device_type") as mock_hw_match:
+            mock_hw_match.return_value = {"matched": False, "device_type": None}
+
+            result = DeviceValidationDetailsView._build_sync_info(libre_device, existing)
+
+        assert result["device_type_synced"] is False
+        assert result["all_synced"] is False
+
+
+class TestImportSingleDeviceLazyValidation:
     """import_single_device must pass api=api to validate_device_for_import when validation is None."""
 
     def test_api_passed_to_validate(self):
@@ -2731,3 +3394,2279 @@ def test_api_passed_to_validate(self):
 
             mock_validate.assert_called_once()
             assert mock_validate.call_args[1].get("api") is mock_api
+
+
+class TestDeviceNamingPreferences:
+    """Test that validation honours use_sysname and strip_domain user preferences."""
+
+    def _setup_no_existing(self, mocks):
+        """Configure mocks so no existing device is found."""
+        (
+            mock_site_model,
+            mock_rack,
+            mock_cluster,
+            mock_role,
+            mock_match_type,
+            mock_find_platform,
+            mock_find_site,
+            mock_device,
+            mock_vm,
+        ) = mocks
+
+        mock_vm.objects.filter.return_value.first.return_value = None
+        mock_device.objects.filter.return_value.first.return_value = None
+        mock_find_site.return_value = {
+            "found": False,
+            "site": None,
+            "match_type": None,
+            "confidence": 0.0,
+        }
+        mock_find_platform.return_value = {
+            "found": False,
+            "platform": None,
+            "match_type": None,
+        }
+        mock_match_type.return_value = {
+            "matched": False,
+            "device_type": None,
+            "match_type": None,
+        }
+        mock_role.objects.all.return_value = []
+        mock_site_model.objects.all.return_value = []
+
+    @patch("virtualization.models.VirtualMachine")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.Device")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.find_matching_site")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.find_matching_platform")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.match_librenms_hardware_to_device_type")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.DeviceRole")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.Cluster")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.Rack")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.Site")
+    def test_resolved_name_uses_sysname_by_default(self, *mocks):
+        """Default use_sysname=True uses sysName for resolved_name."""
+        self._setup_no_existing(mocks)
+        from netbox_librenms_plugin.import_utils import validate_device_for_import
+
+        device_data = {
+            "device_id": 1,
+            "hostname": "10.0.0.1",
+            "sysName": "core-switch",
+        }
+        result = validate_device_for_import(device_data, include_vc_detection=False)
+        assert result["resolved_name"] == "core-switch"
+
+    @patch("virtualization.models.VirtualMachine")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.Device")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.find_matching_site")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.find_matching_platform")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.match_librenms_hardware_to_device_type")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.DeviceRole")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.Cluster")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.Rack")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.Site")
+    def test_resolved_name_uses_hostname_when_sysname_disabled(self, *mocks):
+        """use_sysname=False uses hostname for resolved_name."""
+        self._setup_no_existing(mocks)
+        from netbox_librenms_plugin.import_utils import validate_device_for_import
+
+        device_data = {
+            "device_id": 1,
+            "hostname": "10.0.0.1",
+            "sysName": "core-switch",
+        }
+        result = validate_device_for_import(
+            device_data,
+            include_vc_detection=False,
+            use_sysname=False,
+        )
+        assert result["resolved_name"] == "10.0.0.1"
+
+    @patch("virtualization.models.VirtualMachine")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.Device")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.find_matching_site")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.find_matching_platform")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.match_librenms_hardware_to_device_type")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.DeviceRole")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.Cluster")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.Rack")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.Site")
+    def test_resolved_name_strips_domain(self, *mocks):
+        """strip_domain=True strips the domain suffix."""
+        self._setup_no_existing(mocks)
+        from netbox_librenms_plugin.import_utils import validate_device_for_import
+
+        device_data = {
+            "device_id": 1,
+            "hostname": "switch-01.example.com",
+            "sysName": "switch-01.example.com",
+        }
+        result = validate_device_for_import(
+            device_data,
+            include_vc_detection=False,
+            strip_domain=True,
+        )
+        assert result["resolved_name"] == "switch-01"
+
+    @patch("virtualization.models.VirtualMachine")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.Device")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.find_matching_site")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.find_matching_platform")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.match_librenms_hardware_to_device_type")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.DeviceRole")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.Cluster")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.Rack")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.Site")
+    def test_duplicate_detection_uses_resolved_name(self, *mocks):
+        """Duplicate detection should match against the resolved name, not raw hostname."""
+        self._setup_no_existing(mocks)
+
+        # Unpack using same order as _setup_no_existing / @patch decorators (bottom-up)
+        (
+            _mock_site,
+            _mock_rack,
+            _mock_cluster,
+            _mock_role,
+            _mock_hw,
+            _mock_platform,
+            _mock_find_site,
+            mock_device,
+            _mock_vm,
+        ) = mocks
+        existing = MagicMock()
+        existing.name = "core-switch"
+        existing.serial = ""
+        existing.virtual_chassis = None
+        existing.vc_position = None
+        mock_device.objects.filter.return_value.first.side_effect = [None, existing]
+
+        from netbox_librenms_plugin.import_utils import validate_device_for_import
+
+        device_data = {
+            "device_id": 999,
+            "hostname": "10.0.0.1",
+            "sysName": "core-switch",
+        }
+        result = validate_device_for_import(device_data, include_vc_detection=False)
+
+        assert result["existing_device"] == existing
+        assert result["existing_match_type"] == "hostname"
+
+    @patch("virtualization.models.VirtualMachine")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.Device")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.find_matching_site")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.find_matching_platform")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.match_librenms_hardware_to_device_type")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.DeviceRole")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.Cluster")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.Rack")
+    @patch("netbox_librenms_plugin.import_utils.device_operations.Site")
+    def test_backward_compatible_defaults(self, *mocks):
+        """Calling without naming params produces resolved_name in result."""
+        self._setup_no_existing(mocks)
+        from netbox_librenms_plugin.import_utils import validate_device_for_import
+
+        device_data = {
+            "device_id": 1,
+            "hostname": "switch-01",
+        }
+        result = validate_device_for_import(device_data, include_vc_detection=False)
+        assert "resolved_name" in result
+        assert result["resolved_name"] == "switch-01"
+
+
+class TestProcessDeviceFilters:
+    """Tests for process_device_filters and related bulk_import utilities."""
+
+    def test_show_disabled_filters_integer_disabled_1(self):
+        """show_disabled=False should exclude devices with disabled==1 (int)."""
+        from unittest.mock import MagicMock, patch
+
+        devices = [
+            {"device_id": 1, "hostname": "a", "disabled": 0, "status": 1},
+            {"device_id": 2, "hostname": "b", "disabled": 1, "status": 1},  # disabled in LibreNMS
+        ]
+        with (
+            patch(
+                "netbox_librenms_plugin.import_utils.bulk_import.get_librenms_devices_for_import",
+                return_value=(devices, False),
+            ),
+            patch(
+                "netbox_librenms_plugin.import_utils.bulk_import.validate_device_for_import",
+                side_effect=lambda d, **kw: {
+                    "resolved_name": d["hostname"],
+                    "is_ready": True,
+                    "can_import": True,
+                    "status": "active",
+                    "existing_device": None,
+                    "import_as_vm": False,
+                    "existing_match_type": None,
+                },
+            ),
+            patch("netbox_librenms_plugin.import_utils.bulk_import.prefetch_vc_data_for_devices"),
+            patch("netbox_librenms_plugin.import_utils.bulk_import.cache"),
+            patch("netbox_librenms_plugin.import_utils.bulk_import.get_cache_metadata_key", return_value="key"),
+            patch(
+                "netbox_librenms_plugin.import_utils.bulk_import.get_validated_device_cache_key", return_value="vkey"
+            ),
+        ):
+            from netbox_librenms_plugin.import_utils.bulk_import import process_device_filters
+
+            api = MagicMock()
+            api.server_key = "default"
+            result = process_device_filters(
+                api, filters={}, vc_detection_enabled=False, clear_cache=False, show_disabled=False
+            )
+
+        # Only enabled device (disabled==0) should be processed
+        assert len(result) == 1
+        assert result[0]["hostname"] == "a"
+
+    def test_show_disabled_keeps_unreachable_enabled_device(self):
+        """show_disabled=False should keep devices that are enabled (disabled==0) even if status==0."""
+        from unittest.mock import MagicMock, patch
+
+        devices = [
+            {"device_id": 1, "hostname": "a", "disabled": 0, "status": 0},  # down but enabled
+            {"device_id": 2, "hostname": "b", "disabled": 1, "status": 0},  # down and disabled
+        ]
+        with (
+            patch(
+                "netbox_librenms_plugin.import_utils.bulk_import.get_librenms_devices_for_import",
+                return_value=(devices, False),
+            ),
+            patch(
+                "netbox_librenms_plugin.import_utils.bulk_import.validate_device_for_import",
+                side_effect=lambda d, **kw: {
+                    "resolved_name": d["hostname"],
+                    "is_ready": True,
+                    "can_import": True,
+                    "status": "active",
+                    "existing_device": None,
+                    "import_as_vm": False,
+                    "existing_match_type": None,
+                },
+            ),
+            patch("netbox_librenms_plugin.import_utils.bulk_import.prefetch_vc_data_for_devices"),
+            patch("netbox_librenms_plugin.import_utils.bulk_import.cache"),
+            patch("netbox_librenms_plugin.import_utils.bulk_import.get_cache_metadata_key", return_value="key"),
+            patch(
+                "netbox_librenms_plugin.import_utils.bulk_import.get_validated_device_cache_key", return_value="vkey"
+            ),
+        ):
+            from netbox_librenms_plugin.import_utils.bulk_import import process_device_filters
+
+            api = MagicMock()
+            api.server_key = "default"
+            result = process_device_filters(
+                api, filters={}, vc_detection_enabled=False, clear_cache=False, show_disabled=False
+            )
+
+        # Device a is enabled (disabled==0) and should be kept even though status==0
+        assert len(result) == 1
+        assert result[0]["hostname"] == "a"
+
+    def test_show_disabled_true_includes_all(self):
+        """show_disabled=True should include both active and inactive devices."""
+        from unittest.mock import MagicMock, patch
+
+        devices = [
+            {"device_id": 1, "hostname": "a", "status": 1},
+            {"device_id": 2, "hostname": "b", "status": 0},
+        ]
+        with (
+            patch(
+                "netbox_librenms_plugin.import_utils.bulk_import.get_librenms_devices_for_import",
+                return_value=(devices, False),
+            ),
+            patch(
+                "netbox_librenms_plugin.import_utils.bulk_import.validate_device_for_import",
+                side_effect=lambda d, **kw: {
+                    "resolved_name": d["hostname"],
+                    "is_ready": True,
+                    "can_import": True,
+                    "status": "active",
+                    "existing_device": None,
+                    "import_as_vm": False,
+                    "existing_match_type": None,
+                },
+            ),
+            patch("netbox_librenms_plugin.import_utils.bulk_import.prefetch_vc_data_for_devices"),
+            patch("netbox_librenms_plugin.import_utils.bulk_import.cache"),
+            patch("netbox_librenms_plugin.import_utils.bulk_import.get_cache_metadata_key", return_value="key"),
+            patch(
+                "netbox_librenms_plugin.import_utils.bulk_import.get_validated_device_cache_key", return_value="vkey"
+            ),
+        ):
+            from netbox_librenms_plugin.import_utils.bulk_import import process_device_filters
+
+            api = MagicMock()
+            api.server_key = "default"
+            result = process_device_filters(
+                api, filters={}, vc_detection_enabled=False, clear_cache=False, show_disabled=True
+            )
+
+        assert len(result) == 2
+
+    def test_empty_return_helper(self):
+        """_empty_return should return ([], False) when return_cache_status=True, else []."""
+        from netbox_librenms_plugin.import_utils.bulk_import import _empty_return
+
+        assert _empty_return(True) == ([], False)
+        assert _empty_return(False) == []
+
+    def test_bulk_import_devices_uses_resolved_server_key(self):
+        """bulk_import_devices_shared should pass api.server_key to import_single_device."""
+        from unittest.mock import MagicMock, patch
+
+        with (
+            patch("netbox_librenms_plugin.import_utils.bulk_import.LibreNMSAPI") as mock_api_cls,
+            patch("netbox_librenms_plugin.import_utils.bulk_import.import_single_device") as mock_import,
+            patch("netbox_librenms_plugin.import_utils.bulk_import.validate_device_for_import"),
+            patch("netbox_librenms_plugin.import_utils.bulk_import.require_permissions"),
+        ):
+            mock_api = MagicMock()
+            mock_api.server_key = "resolved-key"
+            mock_api.get_device_info.return_value = (True, {"device_id": 1, "hostname": "sw"})
+            mock_api_cls.return_value = mock_api
+            mock_import.return_value = {"success": True, "device": MagicMock(), "is_vm": False}
+
+            user = MagicMock()
+            from netbox_librenms_plugin.import_utils.bulk_import import bulk_import_devices_shared
+
+            bulk_import_devices_shared([1], user=user, server_key=None)
+
+        # The resolved api.server_key ("resolved-key") must be passed, not None
+        assert mock_import.call_args is not None
+        assert mock_import.call_args.kwargs.get("server_key") == "resolved-key"
+
+
+class TestVCPositionHandling:
+    """Test VC position normalization and suggested name generation."""
+
+    def test_clone_vc_data_position_fallback_is_one_based(self):
+        """_clone_virtual_chassis_data fallback must be 1-based (idx+1, not idx)."""
+        from netbox_librenms_plugin.import_utils.virtual_chassis import _clone_virtual_chassis_data
+
+        data = {"is_stack": True, "member_count": 2, "members": [{"serial": "S1"}, {"serial": "S2"}]}
+        result = _clone_virtual_chassis_data(data)
+        positions = [m["position"] for m in result["members"]]
+        # First member: idx=0 → position should be 1, not 0
+        assert positions[0] == 1
+        assert positions[1] == 2
+
+    def test_clone_vc_data_preserves_explicit_positions(self):
+        """_clone_virtual_chassis_data must preserve explicitly set positions."""
+        from netbox_librenms_plugin.import_utils.virtual_chassis import _clone_virtual_chassis_data
+
+        data = {
+            "is_stack": True,
+            "member_count": 2,
+            "members": [{"serial": "S1", "position": 3}, {"serial": "S2", "position": 5}],
+        }
+        result = _clone_virtual_chassis_data(data)
+        assert result["members"][0]["position"] == 3
+        assert result["members"][1]["position"] == 5
+
+    def test_clone_vc_data_bad_position_falls_back_to_one_based(self):
+        """_clone_virtual_chassis_data falls back to idx+1 for non-int position."""
+        from netbox_librenms_plugin.import_utils.virtual_chassis import _clone_virtual_chassis_data
+
+        data = {
+            "is_stack": True,
+            "member_count": 2,
+            "members": [{"serial": "S1", "position": "bad"}, {"serial": "S2", "position": None}],
+        }
+        result = _clone_virtual_chassis_data(data)
+        # idx=0 → fallback 1, idx=1 → fallback 2
+        assert result["members"][0]["position"] == 1
+        assert result["members"][1]["position"] == 2
+
+    def test_suggested_name_uses_position_directly(self):
+        """
+        Suggested name generation must use position directly (not position+1).
+
+        This test verifies that _generate_vc_member_name is called with the
+        already-1-based position value, not position+1.
+        """
+        from netbox_librenms_plugin.import_utils.virtual_chassis import _generate_vc_member_name
+
+        # position=1 should produce name with "1", not "2"
+        name = _generate_vc_member_name("switch-1", 1, pattern="-M{position}")
+        assert name == "switch-1-M1", f"Expected 'switch-1-M1', got '{name}'"
+
+        # position=2 should produce "2", not "3"
+        name = _generate_vc_member_name("switch-1", 2, pattern="-M{position}")
+        assert name == "switch-1-M2", f"Expected 'switch-1-M2', got '{name}'"
+
+    def test_update_vc_member_suggested_names_no_off_by_one(self):
+        """
+        update_vc_member_suggested_names must use stored 1-based positions directly.
+
+        Previously bays_by_depth applied an extra +1 to positions that were
+        already 1-based, producing suggested names like "switch-M2" for position 1.
+        """
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.import_utils.virtual_chassis import (
+            update_vc_member_suggested_names,
+        )
+
+        vc_data = {
+            "is_stack": True,
+            "member_count": 2,
+            "members": [
+                {"serial": "S1", "position": 1},
+                {"serial": "S2", "position": 2},
+            ],
+        }
+
+        with patch(
+            "netbox_librenms_plugin.import_utils.virtual_chassis._load_vc_member_name_pattern",
+            return_value="-M{position}",
+        ):
+            result = update_vc_member_suggested_names(vc_data, "switch-01")
+
+        names = [m["suggested_name"] for m in result["members"]]
+        # Position 1 → "switch-01-M1", NOT "switch-01-M2"
+        assert names[0] == "switch-01-M1", f"Expected 'switch-01-M1' but got {names[0]!r} — off-by-one regression"
+        assert names[1] == "switch-01-M2", f"Expected 'switch-01-M2' but got {names[1]!r} — off-by-one regression"
+
+    def test_update_vc_member_suggested_names_preserves_position(self):
+        """update_vc_member_suggested_names must write final position back to member dict."""
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.import_utils.virtual_chassis import (
+            update_vc_member_suggested_names,
+        )
+
+        vc_data = {
+            "is_stack": True,
+            "member_count": 1,
+            "members": [{"serial": "S1", "position": 3}],
+        }
+
+        with patch(
+            "netbox_librenms_plugin.import_utils.virtual_chassis._load_vc_member_name_pattern",
+            return_value="-M{position}",
+        ):
+            result = update_vc_member_suggested_names(vc_data, "router")
+
+        member = result["members"][0]
+        assert member["position"] == 3
+        assert member["suggested_name"] == "router-M3"
+
+    def test_update_vc_member_suggested_names_fallback_for_zero_position(self):
+        """Position 0 must be replaced with 1-based fallback (idx+1)."""
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.import_utils.virtual_chassis import (
+            update_vc_member_suggested_names,
+        )
+
+        vc_data = {
+            "is_stack": True,
+            "member_count": 2,
+            "members": [{"serial": "S1", "position": 0}, {"serial": "S2", "position": -1}],
+        }
+
+        with patch(
+            "netbox_librenms_plugin.import_utils.virtual_chassis._load_vc_member_name_pattern",
+            return_value="-M{position}",
+        ):
+            result = update_vc_member_suggested_names(vc_data, "sw")
+
+        positions = [m["position"] for m in result["members"]]
+        assert positions[0] == 1, f"Zero position must fall back to 1, got {positions[0]}"
+        assert positions[1] == 2, f"Negative position must fall back to 2 (idx+1), got {positions[1]}"
+
+
+# ---------------------------------------------------------------------------
+# Additional virtual_chassis.py coverage
+# ---------------------------------------------------------------------------
+
+
+class TestEmptyVirtualChassisData:
+    """Tests for empty_virtual_chassis_data helper."""
+
+    def test_returns_expected_structure(self):
+        from netbox_librenms_plugin.import_utils.virtual_chassis import empty_virtual_chassis_data
+
+        result = empty_virtual_chassis_data()
+        assert result["is_stack"] is False
+        assert result["member_count"] == 0
+        assert result["members"] == []
+        assert result["detection_error"] is None
+
+    def test_returns_new_dict_each_call(self):
+        """Each call returns an independent dict (not a shared reference)."""
+        from netbox_librenms_plugin.import_utils.virtual_chassis import empty_virtual_chassis_data
+
+        a = empty_virtual_chassis_data()
+        b = empty_virtual_chassis_data()
+        a["members"].append("x")
+        assert b["members"] == []
+
+
+class TestCloneVirtualChassisDataAdditional:
+    """Additional _clone_virtual_chassis_data edge cases."""
+
+    def test_none_input_returns_empty(self):
+        from netbox_librenms_plugin.import_utils.virtual_chassis import _clone_virtual_chassis_data
+
+        result = _clone_virtual_chassis_data(None)
+        assert result["is_stack"] is False
+        assert result["members"] == []
+
+    def test_empty_dict_returns_empty(self):
+        from netbox_librenms_plugin.import_utils.virtual_chassis import _clone_virtual_chassis_data
+
+        result = _clone_virtual_chassis_data({})
+        assert result["is_stack"] is False
+        assert result["members"] == []
+
+    def test_full_data_defensive_copy(self):
+        """Members list is a new list; mutating it does not affect the source."""
+        from netbox_librenms_plugin.import_utils.virtual_chassis import _clone_virtual_chassis_data
+
+        data = {
+            "is_stack": True,
+            "member_count": 1,
+            "members": [{"serial": "SN1", "position": 1}],
+            "detection_error": None,
+        }
+        result = _clone_virtual_chassis_data(data)
+        result["members"].append({"serial": "SN-NEW", "position": 2})
+        assert len(data["members"]) == 1  # original untouched
+
+    def test_detection_error_preserved(self):
+        """detection_error field from source data is preserved."""
+        from netbox_librenms_plugin.import_utils.virtual_chassis import _clone_virtual_chassis_data
+
+        data = {
+            "is_stack": True,
+            "member_count": 1,
+            "members": [],
+            "detection_error": "Some error",
+        }
+        result = _clone_virtual_chassis_data(data)
+        assert result["detection_error"] == "Some error"
+
+    def test_member_with_zero_position_replaced_by_one_based(self):
+        """A member with position=0 is replaced by idx+1 (1-based)."""
+        from netbox_librenms_plugin.import_utils.virtual_chassis import _clone_virtual_chassis_data
+
+        data = {
+            "is_stack": True,
+            "member_count": 2,
+            "members": [{"serial": "S0", "position": 0}, {"serial": "S2", "position": 2}],
+        }
+        result = _clone_virtual_chassis_data(data)
+        assert result["members"][0]["position"] == 1  # 0 → idx+1 = 1
+        assert result["members"][1]["position"] == 2  # kept as-is
+
+    def test_member_count_falls_back_to_len_when_zero(self):
+        """member_count=0 in source is replaced by len(members)."""
+        from netbox_librenms_plugin.import_utils.virtual_chassis import _clone_virtual_chassis_data
+
+        data = {
+            "is_stack": True,
+            "member_count": 0,
+            "members": [{"serial": "S1", "position": 1}, {"serial": "S2", "position": 2}],
+        }
+        result = _clone_virtual_chassis_data(data)
+        assert result["member_count"] == 2
+
+
+class TestVCCacheKey:
+    """Tests for _vc_cache_key."""
+
+    def test_cache_key_format(self):
+        from netbox_librenms_plugin.import_utils.virtual_chassis import _vc_cache_key
+
+        mock_api = MagicMock()
+        mock_api.server_key = "default"
+        key = _vc_cache_key(mock_api, 42)
+        assert "librenms_vc_detection" in key
+        assert "default" in key
+        assert "42" in key
+
+    def test_cache_key_includes_server_key(self):
+        from netbox_librenms_plugin.import_utils.virtual_chassis import _vc_cache_key
+
+        api_a = MagicMock()
+        api_a.server_key = "server-a"
+        api_b = MagicMock()
+        api_b.server_key = "server-b"
+        assert _vc_cache_key(api_a, 1) != _vc_cache_key(api_b, 1)
+
+    def test_cache_key_differs_for_different_device_ids(self):
+        from netbox_librenms_plugin.import_utils.virtual_chassis import _vc_cache_key
+
+        mock_api = MagicMock()
+        mock_api.server_key = "default"
+        assert _vc_cache_key(mock_api, 1) != _vc_cache_key(mock_api, 2)
+
+    def test_missing_server_key_falls_back_to_default(self):
+        """api without server_key attribute uses 'default' as fallback."""
+        from netbox_librenms_plugin.import_utils.virtual_chassis import _vc_cache_key
+
+        mock_api = MagicMock(spec=[])  # no attributes
+        key = _vc_cache_key(mock_api, 10)
+        assert "default" in key
+
+
+class TestGetVirtualChassisData:
+    """Tests for get_virtual_chassis_data."""
+
+    def test_none_api_returns_empty(self):
+        from netbox_librenms_plugin.import_utils.virtual_chassis import get_virtual_chassis_data
+
+        result = get_virtual_chassis_data(None, 1)
+        assert result["is_stack"] is False
+        assert result["members"] == []
+
+    def test_none_device_id_returns_empty(self):
+        from netbox_librenms_plugin.import_utils.virtual_chassis import get_virtual_chassis_data
+
+        mock_api = MagicMock()
+        result = get_virtual_chassis_data(mock_api, None)
+        assert result["is_stack"] is False
+
+    def test_cache_hit_returns_cloned_data(self):
+        """Cached data is returned without calling detect_virtual_chassis_from_inventory."""
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.import_utils.virtual_chassis import get_virtual_chassis_data
+
+        mock_api = MagicMock()
+        mock_api.server_key = "default"
+        cached = {
+            "is_stack": True,
+            "member_count": 2,
+            "members": [{"serial": "S1", "position": 1}, {"serial": "S2", "position": 2}],
+            "detection_error": None,
+        }
+
+        with (
+            patch("netbox_librenms_plugin.import_utils.virtual_chassis.cache") as mock_cache,
+            patch(
+                "netbox_librenms_plugin.import_utils.virtual_chassis.detect_virtual_chassis_from_inventory"
+            ) as mock_detect,
+        ):
+            mock_cache.get.return_value = cached
+            result = get_virtual_chassis_data(mock_api, 42)
+
+        assert result["is_stack"] is True
+        assert result["member_count"] == 2
+        mock_detect.assert_not_called()
+
+    def test_cache_miss_calls_detect_and_stores_result(self):
+        """On cache miss, detect_virtual_chassis_from_inventory is called and result cached."""
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.import_utils.virtual_chassis import get_virtual_chassis_data
+
+        mock_api = MagicMock()
+        mock_api.server_key = "default"
+        mock_api.cache_timeout = 300
+
+        detection_result = {"is_stack": False, "member_count": 0, "members": []}
+
+        with (
+            patch("netbox_librenms_plugin.import_utils.virtual_chassis.cache") as mock_cache,
+            patch(
+                "netbox_librenms_plugin.import_utils.virtual_chassis.detect_virtual_chassis_from_inventory",
+                return_value=detection_result,
+            ) as mock_detect,
+        ):
+            mock_cache.get.return_value = None  # cache miss
+            result = get_virtual_chassis_data(mock_api, 42)
+
+        mock_detect.assert_called_once_with(mock_api, 42)
+        mock_cache.set.assert_called_once()
+        assert result["is_stack"] is False
+
+    def test_cache_miss_detect_returns_none_stores_empty(self):
+        """When detect returns None (non-stack or API failure), empty result is cached to suppress repeated hits."""
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.import_utils.virtual_chassis import get_virtual_chassis_data
+
+        mock_api = MagicMock()
+        mock_api.server_key = "default"
+        mock_api.cache_timeout = 300
+
+        with (
+            patch("netbox_librenms_plugin.import_utils.virtual_chassis.cache") as mock_cache,
+            patch(
+                "netbox_librenms_plugin.import_utils.virtual_chassis.detect_virtual_chassis_from_inventory",
+                return_value=None,
+            ),
+        ):
+            mock_cache.get.return_value = None
+            result = get_virtual_chassis_data(mock_api, 99)
+
+        mock_cache.set.assert_called_once()
+        set_args = mock_cache.set.call_args
+        cached_val = set_args[0][1]
+        assert cached_val["is_stack"] is False
+        assert cached_val["member_count"] == 0
+        assert result["is_stack"] is False
+
+    def test_force_refresh_bypasses_cache(self):
+        """force_refresh=True skips the cache.get check."""
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.import_utils.virtual_chassis import get_virtual_chassis_data
+
+        mock_api = MagicMock()
+        mock_api.server_key = "default"
+        mock_api.cache_timeout = 300
+
+        with (
+            patch("netbox_librenms_plugin.import_utils.virtual_chassis.cache") as mock_cache,
+            patch(
+                "netbox_librenms_plugin.import_utils.virtual_chassis.detect_virtual_chassis_from_inventory",
+                return_value=None,
+            ),
+        ):
+            mock_cache.get.return_value = {"is_stack": True, "member_count": 1, "members": [], "detection_error": None}
+            get_virtual_chassis_data(mock_api, 1, force_refresh=True)
+
+        # cache.get should NOT have been consulted
+        mock_cache.get.assert_not_called()
+
+
+class TestPrefetchVCData:
+    """Tests for prefetch_vc_data_for_devices."""
+
+    def test_none_api_returns_immediately(self):
+        """None api causes early return without touching get_virtual_chassis_data."""
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.import_utils.virtual_chassis import prefetch_vc_data_for_devices
+
+        with patch("netbox_librenms_plugin.import_utils.virtual_chassis.get_virtual_chassis_data") as mock_get:
+            prefetch_vc_data_for_devices(None, [1, 2, 3])
+
+        mock_get.assert_not_called()
+
+    def test_empty_device_ids_returns_immediately(self):
+        """Empty device_ids list causes early return."""
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.import_utils.virtual_chassis import prefetch_vc_data_for_devices
+
+        mock_api = MagicMock()
+
+        with patch("netbox_librenms_plugin.import_utils.virtual_chassis.get_virtual_chassis_data") as mock_get:
+            prefetch_vc_data_for_devices(mock_api, [])
+
+        mock_get.assert_not_called()
+
+    def test_connection_error_stops_processing(self):
+        """BrokenPipeError / ConnectionError stops the loop (return, not continue)."""
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.import_utils.virtual_chassis import prefetch_vc_data_for_devices
+
+        mock_api = MagicMock()
+
+        with patch(
+            "netbox_librenms_plugin.import_utils.virtual_chassis.get_virtual_chassis_data",
+            side_effect=ConnectionError("Connection reset"),
+        ) as mock_get:
+            prefetch_vc_data_for_devices(mock_api, [1, 2, 3])
+
+        # Only the first call fires before the connection error stops processing
+        assert mock_get.call_count == 1
+
+    def test_broken_pipe_error_stops_processing(self):
+        """BrokenPipeError is treated the same as ConnectionError."""
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.import_utils.virtual_chassis import prefetch_vc_data_for_devices
+
+        mock_api = MagicMock()
+
+        with patch(
+            "netbox_librenms_plugin.import_utils.virtual_chassis.get_virtual_chassis_data",
+            side_effect=BrokenPipeError("Pipe broken"),
+        ) as mock_get:
+            prefetch_vc_data_for_devices(mock_api, [10, 20])
+
+        assert mock_get.call_count == 1
+
+    def test_generic_exception_continues_to_next_device(self):
+        """Non-connection exceptions are logged but processing continues."""
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.import_utils.virtual_chassis import prefetch_vc_data_for_devices
+
+        mock_api = MagicMock()
+
+        with patch(
+            "netbox_librenms_plugin.import_utils.virtual_chassis.get_virtual_chassis_data",
+            side_effect=ValueError("Unexpected"),
+        ) as mock_get:
+            prefetch_vc_data_for_devices(mock_api, [1, 2, 3])
+
+        # All devices attempted despite the error
+        assert mock_get.call_count == 3
+
+    def test_success_calls_get_for_each_device(self):
+        """All device IDs are prefetched when no errors occur."""
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.import_utils.virtual_chassis import prefetch_vc_data_for_devices
+
+        mock_api = MagicMock()
+
+        with patch("netbox_librenms_plugin.import_utils.virtual_chassis.get_virtual_chassis_data") as mock_get:
+            prefetch_vc_data_for_devices(mock_api, [10, 20, 30])
+
+        assert mock_get.call_count == 3
+
+
+class TestDetectVirtualChassisFromInventory:
+    """Tests for detect_virtual_chassis_from_inventory."""
+
+    def test_no_root_items_returns_none(self):
+        """Returns None when get_inventory_filtered returns no root items."""
+        from netbox_librenms_plugin.import_utils.virtual_chassis import detect_virtual_chassis_from_inventory
+
+        mock_api = MagicMock()
+        mock_api.get_device_info.return_value = (True, {"sysName": "sw1"})
+        mock_api.get_inventory_filtered.return_value = (False, None)
+
+        result = detect_virtual_chassis_from_inventory(mock_api, 1)
+        assert result is None
+
+    def test_empty_root_items_returns_none(self):
+        """Returns None when root items list is empty."""
+        from netbox_librenms_plugin.import_utils.virtual_chassis import detect_virtual_chassis_from_inventory
+
+        mock_api = MagicMock()
+        mock_api.get_device_info.return_value = (True, {"sysName": "sw1"})
+        mock_api.get_inventory_filtered.return_value = (True, [])
+
+        result = detect_virtual_chassis_from_inventory(mock_api, 1)
+        assert result is None
+
+    def test_no_stack_or_chassis_parent_returns_none(self):
+        """Returns None when no root item has class 'stack' or 'chassis'."""
+        from netbox_librenms_plugin.import_utils.virtual_chassis import detect_virtual_chassis_from_inventory
+
+        mock_api = MagicMock()
+        mock_api.get_device_info.return_value = (True, {"sysName": "sw1"})
+        mock_api.get_inventory_filtered.return_value = (
+            True,
+            [{"entPhysicalClass": "other", "entPhysicalIndex": 1}],
+        )
+
+        result = detect_virtual_chassis_from_inventory(mock_api, 1)
+        assert result is None
+
+    def test_single_child_chassis_returns_none(self):
+        """Returns None when only one child chassis is found (not a stack)."""
+
+        from netbox_librenms_plugin.import_utils.virtual_chassis import detect_virtual_chassis_from_inventory
+
+        mock_api = MagicMock()
+        mock_api.get_device_info.return_value = (True, {"sysName": "sw1"})
+        mock_api.get_inventory_filtered.side_effect = [
+            (True, [{"entPhysicalClass": "stack", "entPhysicalIndex": 100}]),
+            (True, [{"entPhysicalClass": "chassis", "entPhysicalIndex": 200}]),
+        ]
+
+        result = detect_virtual_chassis_from_inventory(mock_api, 1)
+        assert result is None
+
+    def test_stack_detected_with_two_chassis(self):
+        """Returns stack dict when two or more chassis are found under the parent."""
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.import_utils.virtual_chassis import detect_virtual_chassis_from_inventory
+
+        mock_api = MagicMock()
+        mock_api.get_device_info.return_value = (True, {"sysName": "sw1"})
+        mock_api.get_inventory_filtered.side_effect = [
+            (True, [{"entPhysicalClass": "stack", "entPhysicalIndex": 100}]),
+            (
+                True,
+                [
+                    {
+                        "entPhysicalClass": "chassis",
+                        "entPhysicalIndex": 201,
+                        "entPhysicalParentRelPos": 1,
+                        "entPhysicalSerialNum": "SN1",
+                        "entPhysicalModelName": "C9300-48P",
+                        "entPhysicalName": "Switch 1",
+                        "entPhysicalDescr": "Cisco Catalyst 9300",
+                    },
+                    {
+                        "entPhysicalClass": "chassis",
+                        "entPhysicalIndex": 202,
+                        "entPhysicalParentRelPos": 2,
+                        "entPhysicalSerialNum": "SN2",
+                        "entPhysicalModelName": "C9300-48P",
+                        "entPhysicalName": "Switch 2",
+                        "entPhysicalDescr": "Cisco Catalyst 9300",
+                    },
+                ],
+            ),
+        ]
+
+        with patch(
+            "netbox_librenms_plugin.import_utils.virtual_chassis._load_vc_member_name_pattern",
+            return_value="-M{position}",
+        ):
+            result = detect_virtual_chassis_from_inventory(mock_api, 1)
+
+        assert result is not None
+        assert result["is_stack"] is True
+        assert result["member_count"] == 2
+        assert len(result["members"]) == 2
+        assert result["members"][0]["serial"] == "SN1"
+        assert result["members"][1]["serial"] == "SN2"
+
+    def test_stack_members_sorted_by_position(self):
+        """Members are sorted by position ascending."""
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.import_utils.virtual_chassis import detect_virtual_chassis_from_inventory
+
+        mock_api = MagicMock()
+        mock_api.get_device_info.return_value = (True, {"sysName": "sw1"})
+        mock_api.get_inventory_filtered.side_effect = [
+            (True, [{"entPhysicalClass": "stack", "entPhysicalIndex": 100}]),
+            (
+                True,
+                [
+                    {"entPhysicalClass": "chassis", "entPhysicalParentRelPos": 3, "entPhysicalIndex": 203},
+                    {"entPhysicalClass": "chassis", "entPhysicalParentRelPos": 1, "entPhysicalIndex": 201},
+                    {"entPhysicalClass": "chassis", "entPhysicalParentRelPos": 2, "entPhysicalIndex": 202},
+                ],
+            ),
+        ]
+
+        with patch(
+            "netbox_librenms_plugin.import_utils.virtual_chassis._load_vc_member_name_pattern",
+            return_value="-M{position}",
+        ):
+            result = detect_virtual_chassis_from_inventory(mock_api, 1)
+
+        positions = [m["position"] for m in result["members"]]
+        assert positions == [1, 2, 3]
+
+    def test_zero_position_replaced_by_one_based_index(self):
+        """entPhysicalParentRelPos=0 is replaced by idx+1."""
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.import_utils.virtual_chassis import detect_virtual_chassis_from_inventory
+
+        mock_api = MagicMock()
+        mock_api.get_device_info.return_value = (True, {"sysName": "sw1"})
+        mock_api.get_inventory_filtered.side_effect = [
+            (True, [{"entPhysicalClass": "stack", "entPhysicalIndex": 100}]),
+            (
+                True,
+                [
+                    {"entPhysicalClass": "chassis", "entPhysicalParentRelPos": 0, "entPhysicalIndex": 201},
+                    {"entPhysicalClass": "chassis", "entPhysicalParentRelPos": 2, "entPhysicalIndex": 202},
+                ],
+            ),
+        ]
+
+        with patch(
+            "netbox_librenms_plugin.import_utils.virtual_chassis._load_vc_member_name_pattern",
+            return_value="-M{position}",
+        ):
+            result = detect_virtual_chassis_from_inventory(mock_api, 1)
+
+        positions = [m["position"] for m in result["members"]]
+        assert 0 not in positions
+        assert 1 in positions
+
+    def test_no_master_name_uses_member_prefix(self):
+        """When device_info has no sysName/hostname, suggested_name uses 'Member-N'."""
+
+        from netbox_librenms_plugin.import_utils.virtual_chassis import detect_virtual_chassis_from_inventory
+
+        mock_api = MagicMock()
+        mock_api.get_device_info.return_value = (False, None)  # no master name
+        mock_api.get_inventory_filtered.side_effect = [
+            (True, [{"entPhysicalClass": "stack", "entPhysicalIndex": 100}]),
+            (
+                True,
+                [
+                    {"entPhysicalClass": "chassis", "entPhysicalParentRelPos": 1, "entPhysicalIndex": 201},
+                    {"entPhysicalClass": "chassis", "entPhysicalParentRelPos": 2, "entPhysicalIndex": 202},
+                ],
+            ),
+        ]
+
+        result = detect_virtual_chassis_from_inventory(mock_api, 1)
+
+        assert result is not None
+        assert result["members"][0]["suggested_name"].startswith("Member-")
+
+    def test_child_items_fetch_fails_returns_none(self):
+        """Returns None when the second get_inventory_filtered call fails."""
+        from netbox_librenms_plugin.import_utils.virtual_chassis import detect_virtual_chassis_from_inventory
+
+        mock_api = MagicMock()
+        mock_api.get_device_info.return_value = (True, {"sysName": "sw1"})
+        mock_api.get_inventory_filtered.side_effect = [
+            (True, [{"entPhysicalClass": "stack", "entPhysicalIndex": 100}]),
+            (False, None),  # child fetch fails
+        ]
+
+        result = detect_virtual_chassis_from_inventory(mock_api, 1)
+        assert result is None
+
+    def test_exception_returns_none(self):
+        """Unhandled exception inside the function returns None."""
+        from netbox_librenms_plugin.import_utils.virtual_chassis import detect_virtual_chassis_from_inventory
+
+        mock_api = MagicMock()
+        mock_api.get_device_info.side_effect = RuntimeError("Unexpected")
+
+        result = detect_virtual_chassis_from_inventory(mock_api, 1)
+        assert result is None
+
+
+class TestLoadVCMemberNamePattern:
+    """Tests for _load_vc_member_name_pattern."""
+
+    def test_returns_pattern_from_settings(self):
+        """Returns vc_member_name_pattern from LibreNMSSettings when found."""
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.import_utils.virtual_chassis import _load_vc_member_name_pattern
+
+        mock_settings = MagicMock()
+        mock_settings.vc_member_name_pattern = "-SW{position}"
+
+        with patch("netbox_librenms_plugin.models.LibreNMSSettings") as mock_cls:
+            mock_cls.objects.order_by.return_value.first.return_value = mock_settings
+            result = _load_vc_member_name_pattern()
+
+        assert result == "-SW{position}"
+
+    def test_no_settings_returns_default(self):
+        """Returns '-M{position}' when LibreNMSSettings.objects.order_by().first() returns None."""
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.import_utils.virtual_chassis import _load_vc_member_name_pattern
+
+        with patch("netbox_librenms_plugin.models.LibreNMSSettings") as mock_cls:
+            mock_cls.objects.order_by.return_value.first.return_value = None
+            result = _load_vc_member_name_pattern()
+
+        assert result == "-M{position}"
+
+    def test_exception_returns_default(self):
+        """Returns '-M{position}' when the DB query raises an exception."""
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.import_utils.virtual_chassis import _load_vc_member_name_pattern
+
+        with patch("netbox_librenms_plugin.models.LibreNMSSettings") as mock_cls:
+            mock_cls.objects.order_by.side_effect = Exception("DB offline")
+            result = _load_vc_member_name_pattern()
+
+        assert result == "-M{position}"
+
+
+class TestGenerateVCMemberNameAdditional:
+    """Additional tests for _generate_vc_member_name."""
+
+    def test_with_serial_in_pattern(self):
+        """Pattern using {serial} placeholder substitutes the serial number."""
+        from netbox_librenms_plugin.import_utils.virtual_chassis import _generate_vc_member_name
+
+        name = _generate_vc_member_name("switch-1", 2, serial="ABC123", pattern=" [{serial}]")
+        assert name == "switch-1 [ABC123]"
+
+    def test_empty_serial_produces_empty_brackets(self):
+        """Empty serial with {serial} pattern results in empty brackets."""
+        from netbox_librenms_plugin.import_utils.virtual_chassis import _generate_vc_member_name
+
+        name = _generate_vc_member_name("switch-1", 1, serial="", pattern=" [{serial}]")
+        assert name == "switch-1 []"
+
+    def test_invalid_placeholder_falls_back_to_default(self):
+        """A KeyError from an unknown placeholder triggers the '-M{position}' fallback."""
+        from netbox_librenms_plugin.import_utils.virtual_chassis import _generate_vc_member_name
+
+        name = _generate_vc_member_name("switch-1", 3, pattern="-{nonexistent_key}")
+        assert name == "switch-1-M3"
+
+    def test_none_pattern_loads_from_settings(self):
+        """When pattern=None, _load_vc_member_name_pattern is called to fetch the pattern."""
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.import_utils.virtual_chassis import _generate_vc_member_name
+
+        with patch(
+            "netbox_librenms_plugin.import_utils.virtual_chassis._load_vc_member_name_pattern",
+            return_value="-M{position}",
+        ) as mock_load:
+            name = _generate_vc_member_name("router", 5, pattern=None)
+
+        mock_load.assert_called_once()
+        assert name == "router-M5"
+
+    def test_master_name_placeholder(self):
+        """Pattern can also reference {master_name}."""
+        from netbox_librenms_plugin.import_utils.virtual_chassis import _generate_vc_member_name
+
+        name = _generate_vc_member_name("sw", 2, pattern="-{master_name}-pos{position}")
+        assert name == "sw-sw-pos2"
+
+
+class TestUpdateVCMemberSuggestedNamesAdditional:
+    """Additional tests for update_vc_member_suggested_names."""
+
+    def test_not_stack_returns_vc_data_unchanged(self):
+        """When is_stack=False, the function returns immediately without modifying members."""
+        from netbox_librenms_plugin.import_utils.virtual_chassis import update_vc_member_suggested_names
+
+        vc_data = {
+            "is_stack": False,
+            "members": [{"serial": "S1", "position": 1, "suggested_name": "old-name"}],
+        }
+        result = update_vc_member_suggested_names(vc_data, "sw")
+        # suggested_name must not be regenerated
+        assert result["members"][0]["suggested_name"] == "old-name"
+
+    def test_none_vc_data_returns_none(self):
+        """None input is returned as-is (falsy guard)."""
+        from netbox_librenms_plugin.import_utils.virtual_chassis import update_vc_member_suggested_names
+
+        result = update_vc_member_suggested_names(None, "sw")
+        assert result is None
+
+    def test_no_members_returns_empty_members(self):
+        """is_stack=True with empty members list processes without error."""
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.import_utils.virtual_chassis import update_vc_member_suggested_names
+
+        vc_data = {"is_stack": True, "members": []}
+
+        with patch(
+            "netbox_librenms_plugin.import_utils.virtual_chassis._load_vc_member_name_pattern",
+            return_value="-M{position}",
+        ):
+            result = update_vc_member_suggested_names(vc_data, "sw")
+
+        assert result["members"] == []
+
+
+class TestCreateVirtualChassisWithMembers:
+    """Tests for create_virtual_chassis_with_members."""
+
+    def test_raises_when_vc_create_fails(self):
+        """Exception from VirtualChassis.objects.create is re-raised to the caller."""
+        from contextlib import contextmanager
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.import_utils.virtual_chassis import create_virtual_chassis_with_members
+
+        master_device = MagicMock()
+        master_device.name = "sw1"
+        master_device.pk = 1
+        master_device.serial = ""
+
+        @contextmanager
+        def mock_atomic():
+            yield
+
+        with (
+            patch(
+                "netbox_librenms_plugin.import_utils.virtual_chassis.transaction.atomic",
+                mock_atomic,
+            ),
+            patch(
+                "netbox_librenms_plugin.import_utils.virtual_chassis._generate_vc_member_name",
+                return_value="sw1-M1",
+            ),
+            patch("netbox_librenms_plugin.import_utils.virtual_chassis.Device") as mock_device_cls,
+            patch("netbox_librenms_plugin.import_utils.virtual_chassis.VirtualChassis") as mock_vc_cls,
+            patch(
+                "netbox_librenms_plugin.import_utils.virtual_chassis._load_vc_member_name_pattern",
+                return_value="-M{position}",
+            ),
+        ):
+            mock_device_cls.objects.filter.return_value.exclude.return_value.exists.return_value = False
+            mock_vc_cls.objects.create.side_effect = Exception("DB error")
+
+            import pytest
+
+            with pytest.raises(Exception, match="DB error"):
+                create_virtual_chassis_with_members(master_device, [], {"device_id": 1})
+
+    def test_success_with_no_members(self):
+        """Happy path with empty members_info creates VC and returns it."""
+        from contextlib import contextmanager
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.import_utils.virtual_chassis import create_virtual_chassis_with_members
+
+        master_device = MagicMock()
+        master_device.name = "sw1"
+        master_device.pk = 1
+        master_device.serial = ""
+
+        mock_vc = MagicMock()
+        mock_vc.members.count.return_value = 1
+
+        @contextmanager
+        def mock_atomic():
+            yield
+
+        with (
+            patch(
+                "netbox_librenms_plugin.import_utils.virtual_chassis.transaction.atomic",
+                mock_atomic,
+            ),
+            patch(
+                "netbox_librenms_plugin.import_utils.virtual_chassis._generate_vc_member_name",
+                return_value="sw1-M1",
+            ),
+            patch("netbox_librenms_plugin.import_utils.virtual_chassis.Device") as mock_device_cls,
+            patch("netbox_librenms_plugin.import_utils.virtual_chassis.VirtualChassis") as mock_vc_cls,
+            patch(
+                "netbox_librenms_plugin.import_utils.virtual_chassis._load_vc_member_name_pattern",
+                return_value="-M{position}",
+            ),
+        ):
+            mock_device_cls.objects.filter.return_value.exclude.return_value.exists.return_value = False
+            mock_vc_cls.objects.create.return_value = mock_vc
+
+            result = create_virtual_chassis_with_members(master_device, [], {"device_id": 1})
+
+        assert result == mock_vc
+        mock_vc_cls.objects.create.assert_called_once()
+
+
+class TestBulkImportCancellation:
+    """Test that bulk_import_devices_shared respects RQ and DB cancellation."""
+
+    def _run_bulk_import(self, mock_rq_job=None, db_status="running", device_ids=None):
+        """Helper: run bulk_import with provided mocks, return import call count."""
+        from unittest.mock import MagicMock, patch
+
+        if device_ids is None:
+            device_ids = [1, 2, 3, 4, 5, 6]
+
+        job = MagicMock()
+        job.job.job_id = "test-uuid"
+        job_status = MagicMock()
+        job_status.value = db_status
+        job.job.status = job_status
+        job.logger = MagicMock()
+
+        with (
+            patch("netbox_librenms_plugin.import_utils.bulk_import.LibreNMSAPI") as mock_api_cls,
+            patch("netbox_librenms_plugin.import_utils.bulk_import.import_single_device") as mock_import,
+            patch("netbox_librenms_plugin.import_utils.bulk_import.validate_device_for_import"),
+            patch("netbox_librenms_plugin.import_utils.bulk_import.require_permissions"),
+            # Inline imports in the loop use django_rq.get_queue / rq.job.Job directly
+            patch("django_rq.get_queue") as mock_get_queue,
+            patch("rq.job.Job") as mock_rqjob_cls,
+        ):
+            mock_api = MagicMock()
+            mock_api.server_key = "default"
+            mock_api.get_device_info.return_value = (True, {"device_id": 1, "hostname": "sw"})
+            mock_api_cls.return_value = mock_api
+            mock_import.return_value = {"success": True, "device": MagicMock(), "is_vm": False}
+
+            if mock_rq_job is not None:
+                mock_conn = MagicMock()
+                mock_queue = MagicMock()
+                mock_queue.connection = mock_conn
+                mock_get_queue.return_value = mock_queue
+                mock_rqjob_cls.fetch.return_value = mock_rq_job
+            else:
+                # Simulate RQ unavailable — get_queue raises, triggers DB fallback
+                mock_get_queue.side_effect = Exception("RQ unavailable")
+
+            from netbox_librenms_plugin.import_utils.bulk_import import bulk_import_devices_shared
+
+            result = bulk_import_devices_shared(device_ids, user=MagicMock(), server_key=None, job=job)
+
+            return mock_import.call_count, result
+
+    def test_rq_stopped_cancels_import_loop(self):
+        """When RQ job is_stopped, import loop should break early."""
+        rq_job = MagicMock()
+        rq_job.is_stopped = True
+        rq_job.is_failed = False
+        rq_job.get_status.return_value = "stopped"
+
+        # With 6 devices and RQ stopped on first check (idx=1), at most 1 device processed
+        count, result = self._run_bulk_import(mock_rq_job=rq_job, device_ids=[1, 2, 3, 4, 5, 6])
+        assert count == 0  # break before first import
+        assert result.get("cancelled") is True
+
+    def test_rq_failed_cancels_import_loop(self):
+        """When RQ job is_failed, import loop should break early."""
+        rq_job = MagicMock()
+        rq_job.is_stopped = False
+        rq_job.is_failed = True
+        rq_job.get_status.return_value = "failed"
+
+        count, result = self._run_bulk_import(mock_rq_job=rq_job, device_ids=[1, 2, 3, 4, 5, 6])
+        assert count == 0
+        assert result.get("cancelled") is True
+
+    def test_rq_unavailable_falls_back_to_db_check(self):
+        """When RQ is unavailable, DB status check is used as fallback."""
+        # mock_rq_job=None triggers the side_effect=Exception path
+        count, result = self._run_bulk_import(mock_rq_job=None, db_status="failed", device_ids=[1])
+        # With DB status "failed", import should not run
+        assert count == 0
+        assert result.get("cancelled") is True
+
+    def test_db_errored_status_also_terminates_loop(self):
+        """When DB job status is 'errored', import loop should terminate early."""
+        count, result = self._run_bulk_import(mock_rq_job=None, db_status="errored", device_ids=[1, 2, 3])
+        assert count == 0
+        assert result.get("cancelled") is True
+
+    def test_healthy_job_runs_all_devices(self):
+        """When job is healthy, all devices should be imported."""
+        rq_job = MagicMock()
+        rq_job.is_stopped = False
+        rq_job.is_failed = False
+        rq_job.get_status.return_value = "started"
+
+        count, result = self._run_bulk_import(mock_rq_job=rq_job, device_ids=[1, 2, 3])
+        assert count == 3
+        assert result.get("cancelled") is False
+
+
+# ---------------------------------------------------------------------------
+# Tests for VC permission guard in bulk_import_devices_shared (closes #31)
+# ---------------------------------------------------------------------------
+
+
+class TestBulkImportVCPermission:
+    """Test that dcim.add_virtualchassis is checked before creating a VirtualChassis."""
+
+    def _make_stack_validation(self):
+        from unittest.mock import MagicMock
+
+        v = MagicMock()
+        v.get.side_effect = lambda k, d=None: {
+            "is_ready": True,
+            "import_as_vm": False,
+            "existing_device": None,
+            "virtual_chassis": {
+                "is_stack": True,
+                "members": [
+                    {"serial": "SN-A", "position": 1},
+                    {"serial": "SN-B", "position": 2},
+                ],
+            },
+        }.get(k, d)
+        return v
+
+    def test_vc_creation_skipped_without_vc_permission(self):
+        """User lacks dcim.add_virtualchassis → VC skipped, device import still succeeds (closes #31)."""
+        from unittest.mock import MagicMock, patch
+
+        mock_device = MagicMock()
+        user = MagicMock()
+        user.has_perm.side_effect = lambda p: p != "dcim.add_virtualchassis"
+
+        with (
+            patch("netbox_librenms_plugin.import_utils.bulk_import.require_permissions"),
+            patch("netbox_librenms_plugin.import_utils.bulk_import.LibreNMSAPI"),
+            patch(
+                "netbox_librenms_plugin.import_utils.bulk_import.validate_device_for_import",
+                return_value=self._make_stack_validation(),
+            ),
+            patch(
+                "netbox_librenms_plugin.import_utils.bulk_import.import_single_device",
+                return_value={"success": True, "device": mock_device, "message": "ok", "is_vm": False},
+            ),
+            patch(
+                "netbox_librenms_plugin.import_utils.bulk_import.create_virtual_chassis_with_members",
+            ) as mock_create_vc,
+        ):
+            from netbox_librenms_plugin.import_utils.bulk_import import bulk_import_devices_shared
+
+            result = bulk_import_devices_shared(
+                device_ids=[1],
+                user=user,
+                libre_devices_cache={1: {"device_id": 1, "hostname": "sw"}},
+            )
+
+        mock_create_vc.assert_not_called()
+        assert len(result["success"]) == 1
+        assert result["virtual_chassis_created"] == 0
+
+    def test_vc_creation_proceeds_with_vc_permission(self):
+        """User has dcim.add_virtualchassis → VC creation proceeds normally."""
+        from unittest.mock import MagicMock, patch
+
+        mock_device = MagicMock()
+        mock_vc = MagicMock()
+        mock_vc.name = "VC-Stack"
+        user = MagicMock()
+        user.has_perm.return_value = True
+
+        with (
+            patch("netbox_librenms_plugin.import_utils.bulk_import.require_permissions"),
+            patch("netbox_librenms_plugin.import_utils.bulk_import.LibreNMSAPI"),
+            patch(
+                "netbox_librenms_plugin.import_utils.bulk_import.validate_device_for_import",
+                return_value=self._make_stack_validation(),
+            ),
+            patch(
+                "netbox_librenms_plugin.import_utils.bulk_import.import_single_device",
+                return_value={"success": True, "device": mock_device, "message": "ok", "is_vm": False},
+            ),
+            patch(
+                "netbox_librenms_plugin.import_utils.bulk_import.create_virtual_chassis_with_members",
+                return_value=mock_vc,
+            ) as mock_create_vc,
+        ):
+            from netbox_librenms_plugin.import_utils.bulk_import import bulk_import_devices_shared
+
+            result = bulk_import_devices_shared(
+                device_ids=[1],
+                user=user,
+                libre_devices_cache={1: {"device_id": 1, "hostname": "sw"}},
+            )
+
+        mock_create_vc.assert_called_once()
+        assert result["virtual_chassis_created"] == 1
+
+
+# ---------------------------------------------------------------------------
+# Tests for DeviceValidationDetailsView._build_id_server_info
+# ---------------------------------------------------------------------------
+
+
+class TestBuildIdServerInfo:
+    """Test DeviceValidationDetailsView._build_id_server_info method."""
+
+    def _make_device(self, librenms_id_value):
+        from unittest.mock import MagicMock
+
+        device = MagicMock()
+        device.custom_field_data = {"librenms_id": librenms_id_value}
+        return device
+
+    def test_returns_none_for_legacy_int(self):
+        from netbox_librenms_plugin.views.imports.actions import DeviceValidationDetailsView
+
+        device = self._make_device(42)
+        result = DeviceValidationDetailsView._build_id_server_info(device)
+        assert result is None
+
+    def test_returns_none_for_missing_cf(self):
+        from netbox_librenms_plugin.views.imports.actions import DeviceValidationDetailsView
+
+        device = self._make_device(None)
+        result = DeviceValidationDetailsView._build_id_server_info(device)
+        assert result is None
+
+    def test_single_server_resolves_display_name(self):
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.views.imports.actions import DeviceValidationDetailsView
+
+        device = self._make_device({"production": 42})
+        plugins_cfg = {
+            "netbox_librenms_plugin": {
+                "servers": {
+                    "production": {"display_name": "Production LibreNMS", "librenms_url": "https://prod.example.com"},
+                }
+            }
+        }
+        with patch("django.conf.settings") as mock_settings:
+            mock_settings.PLUGINS_CONFIG = plugins_cfg
+            result = DeviceValidationDetailsView._build_id_server_info(device)
+
+        assert result is not None
+        assert len(result) == 1
+        assert result[0]["server_key"] == "production"
+        assert result[0]["display_name"] == "Production LibreNMS"
+        assert result[0]["device_id"] == 42
+
+    def test_unconfigured_server_uses_key_as_display_name(self):
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.views.imports.actions import DeviceValidationDetailsView
+
+        device = self._make_device({"deleted-server": 77})
+        plugins_cfg = {"netbox_librenms_plugin": {"servers": {}}}
+        with patch("django.conf.settings") as mock_settings:
+            mock_settings.PLUGINS_CONFIG = plugins_cfg
+            result = DeviceValidationDetailsView._build_id_server_info(device)
+
+        assert result is not None
+        assert result[0]["display_name"] == "deleted-server"
+
+    def test_empty_dict_returns_none(self):
+        from netbox_librenms_plugin.views.imports.actions import DeviceValidationDetailsView
+
+        device = self._make_device({})
+        result = DeviceValidationDetailsView._build_id_server_info(device)
+        assert result is None
+
+
+# ---------------------------------------------------------------------------
+# Tests for _refresh_existing_device sys_name fallback fix
+# ---------------------------------------------------------------------------
+
+
+class TestRefreshExistingDeviceSysNameFallback:
+    """Test that _refresh_existing_device tries sys_name even when hostname is empty."""
+
+    def test_sysname_used_when_hostname_empty(self):
+        """When hostname is empty but sys_name matches, the device is found in validation."""
+        from unittest.mock import MagicMock, patch
+
+        from netbox_librenms_plugin.import_utils.bulk_import import _refresh_existing_device
+
+        mock_device = MagicMock()
+        mock_device.pk = 99
+        mock_device.name = "router-01"
+        mock_device.custom_field_data = {"librenms_id": None}
+
+        libre_device = {
+            "device_id": 55,
+            "hostname": "",  # empty hostname
+            "sysName": "router-01",
+            "serial": "SN-MATCH",
+        }
+        validation = {
+            "existing_device": None,
+            "existing_vm": None,
+            "import_as_vm": False,
+            "is_ready": False,
+            "can_import": False,
+        }
+
+        # sys_name lookup: filter(name__iexact="router-01") returns mock_device
+        # hostname lookup: filter(name__iexact="") returns None
+        def make_qs(return_val):
+            qs = MagicMock()
+            qs.first.return_value = return_val
+            return qs
+
+        with patch("netbox_librenms_plugin.import_utils.bulk_import.find_by_librenms_id", return_value=None):
+            import dcim.models as dcim_models
+            import virtualization.models as virt_models
+
+            with (
+                patch.object(
+                    dcim_models.Device.objects,
+                    "filter",
+                    side_effect=lambda **kw: make_qs(mock_device if kw.get("name__iexact") == "router-01" else None),
+                ),
+                patch.object(virt_models.VirtualMachine.objects, "filter", return_value=make_qs(None)),
+            ):
+                _refresh_existing_device(validation, libre_device=libre_device, server_key="default")
+
+        assert validation["existing_device"] is mock_device
+
+    def test_hostname_lookup_succeeds_without_sysname(self):
+        """When hostname is non-empty and matches, validation is updated correctly."""
+        from unittest.mock import MagicMock, patch
+
+        from netbox_librenms_plugin.import_utils.bulk_import import _refresh_existing_device
+
+        mock_device = MagicMock()
+        mock_device.pk = 10
+        mock_device.name = "sw-01"
+        mock_device.custom_field_data = {"librenms_id": None}
+
+        libre_device = {
+            "device_id": 10,
+            "hostname": "sw-01",
+            "sysName": "sw-01-sysname",
+            "serial": "",
+        }
+        validation = {
+            "existing_device": None,
+            "existing_vm": None,
+            "import_as_vm": False,
+            "is_ready": False,
+            "can_import": False,
+        }
+
+        def make_qs(return_val):
+            qs = MagicMock()
+            qs.first.return_value = return_val
+            return qs
+
+        with patch("netbox_librenms_plugin.import_utils.bulk_import.find_by_librenms_id", return_value=None):
+            import dcim.models as dcim_models
+            import virtualization.models as virt_models
+
+            with (
+                patch.object(
+                    dcim_models.Device.objects,
+                    "filter",
+                    side_effect=lambda **kw: make_qs(mock_device if kw.get("name__iexact") == "sw-01" else None),
+                ),
+                patch.object(virt_models.VirtualMachine.objects, "filter", return_value=make_qs(None)),
+            ):
+                _refresh_existing_device(validation, libre_device=libre_device, server_key="default")
+
+        assert validation["existing_device"] is mock_device
+
+
+# ---------------------------------------------------------------------------
+# Tests for _get_hostname_for_action helper
+# ---------------------------------------------------------------------------
+
+
+class TestGetHostnameForAction:
+    """Test _get_hostname_for_action helper in actions.py."""
+
+    def test_returns_resolved_name_when_set(self):
+        from unittest.mock import MagicMock
+
+        from netbox_librenms_plugin.views.imports.actions import _get_hostname_for_action
+
+        request = MagicMock()
+        validation = {"resolved_name": "cached-name"}
+        libre_device = {"hostname": "raw-hostname", "sysName": "raw-sysname"}
+
+        result = _get_hostname_for_action(request, validation, libre_device)
+        assert result == "cached-name"
+
+    def test_falls_back_to_determine_device_name(self):
+        from unittest.mock import MagicMock, patch
+
+        from netbox_librenms_plugin.views.imports.actions import _get_hostname_for_action
+
+        request = MagicMock()
+        validation = {}  # no resolved_name
+        libre_device = {"hostname": "host.example.com", "sysName": "host"}
+
+        with patch("netbox_librenms_plugin.views.imports.actions._resolve_naming_preferences") as mock_prefs:
+            mock_prefs.return_value = (False, False)  # use_sysname=False, strip_domain=False
+            with patch("netbox_librenms_plugin.views.imports.actions._determine_device_name") as mock_name:
+                mock_name.return_value = "host.example.com"
+                result = _get_hostname_for_action(request, validation, libre_device)
+
+        assert result == "host.example.com"
+        mock_prefs.assert_called_once_with(request)
+        mock_name.assert_called_once()
+
+
+# ---------------------------------------------------------------------------
+# Tests for _resolve_naming_preferences underscore-variant key support
+# ---------------------------------------------------------------------------
+
+
+class TestResolveNamingPreferencesKeys:
+    """Test that _resolve_naming_preferences handles both hyphenated and underscored keys."""
+
+    def _make_request(self, post=None, get=None):
+        from unittest.mock import MagicMock
+
+        request = MagicMock()
+        request.POST = post or {}
+        request.GET = get or {}
+        request.user = MagicMock()
+        return request
+
+    def test_hyphenated_post_key_use_sysname(self):
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.views.imports.actions import _resolve_naming_preferences
+
+        request = self._make_request(post={"use-sysname-toggle": "on", "strip-domain-toggle": "off"})
+        with patch("netbox_librenms_plugin.views.imports.actions.get_user_pref", return_value=None):
+            use_sysname, strip_domain = _resolve_naming_preferences(request)
+        assert use_sysname is True
+        assert strip_domain is False
+
+    def test_underscored_post_key_use_sysname(self):
+        """Underscore variant 'use_sysname-toggle' should also be recognised."""
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.views.imports.actions import _resolve_naming_preferences
+
+        request = self._make_request(post={"use_sysname-toggle": "on", "strip_domain-toggle": "on"})
+        with patch("netbox_librenms_plugin.views.imports.actions.get_user_pref", return_value=None):
+            use_sysname, strip_domain = _resolve_naming_preferences(request)
+        assert use_sysname is True
+        assert strip_domain is True
+
+    def test_get_key_used_when_not_in_post(self):
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.views.imports.actions import _resolve_naming_preferences
+
+        request = self._make_request(get={"use-sysname-toggle": "off", "strip-domain-toggle": "on"})
+        with patch("netbox_librenms_plugin.views.imports.actions.get_user_pref", return_value=None):
+            use_sysname, strip_domain = _resolve_naming_preferences(request)
+        assert use_sysname is False
+        assert strip_domain is True
+
+    def test_user_pref_used_when_no_toggle_in_request(self):
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.views.imports.actions import _resolve_naming_preferences
+
+        request = self._make_request()
+        with patch("netbox_librenms_plugin.views.imports.actions.get_user_pref") as mock_pref:
+            mock_pref.side_effect = lambda req, key: False if "use_sysname" in key else True
+            use_sysname, strip_domain = _resolve_naming_preferences(request)
+        assert use_sysname is False
+        assert strip_domain is True
+
+    def test_post_takes_precedence_over_user_pref(self):
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.views.imports.actions import _resolve_naming_preferences
+
+        request = self._make_request(post={"use-sysname-toggle": "off"})
+        # user_pref would say True — POST should win
+        with patch("netbox_librenms_plugin.views.imports.actions.get_user_pref", return_value=True):
+            use_sysname, _ = _resolve_naming_preferences(request)
+        assert use_sysname is False
+
+    def test_truthy_string_true_value(self):
+        """'true' and '1' (in addition to 'on') should be treated as True."""
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.views.imports.actions import _resolve_naming_preferences
+
+        for truthy_val in ("true", "True", "TRUE", "1"):
+            request = self._make_request(post={"use-sysname-toggle": truthy_val, "strip-domain-toggle": "off"})
+            with patch("netbox_librenms_plugin.views.imports.actions.get_user_pref", return_value=None):
+                use_sysname, _ = _resolve_naming_preferences(request)
+            assert use_sysname is True, f"Expected True for value {truthy_val!r}"
+
+    def test_falsy_string_false_value(self):
+        """Unrecognised strings should be treated as False."""
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.views.imports.actions import _resolve_naming_preferences
+
+        for falsy_val in ("off", "false", "0", "", "no"):
+            request = self._make_request(post={"use-sysname-toggle": falsy_val, "strip-domain-toggle": "off"})
+            with patch("netbox_librenms_plugin.views.imports.actions.get_user_pref", return_value=None):
+                use_sysname, _ = _resolve_naming_preferences(request)
+            assert use_sysname is False, f"Expected False for value {falsy_val!r}"
+
+
+# ---------------------------------------------------------------------------
+# Tests for vc_domain stack dedup key fix
+# ---------------------------------------------------------------------------
+
+
+class TestVCDomainStackDedup:
+    """Test that bulk_import_devices_shared deduplicates VC creation by member serials."""
+
+    def test_vc_domain_uses_member_serials(self):
+        """vc_domain for two stack members with the same serials should be identical."""
+        # The logic lives inline; test the produced key directly from vc_data
+        members = [
+            {"serial": "SN100", "position": 1},
+            {"serial": "SN200", "position": 2},
+        ]
+        member_serials = sorted(m.get("serial") for m in members if m.get("serial"))
+        vc_domain = f"librenms-stack-{','.join(member_serials)}"
+
+        # Same members from a different device's perspective should produce the same key
+        assert vc_domain == "librenms-stack-SN100,SN200"
+
+    def test_vc_domain_fallback_to_device_id_when_no_serials(self):
+        """When no member serials are available, device_id is used as fallback."""
+        members = [
+            {"position": 1},
+            {"position": 2},
+        ]
+        member_serials = sorted(m.get("serial") for m in members if m.get("serial"))
+        device_id = 42
+        vc_domain = f"librenms-stack-{','.join(member_serials)}" if member_serials else f"librenms-{device_id}"
+        assert vc_domain == "librenms-42"
+
+    def test_different_stacks_produce_different_keys(self):
+        """Two stacks with different serials produce distinct dedup keys."""
+        members_a = [{"serial": "SN-A1"}, {"serial": "SN-A2"}]
+        members_b = [{"serial": "SN-B1"}, {"serial": "SN-B2"}]
+        key_a = f"librenms-stack-{','.join(sorted(m['serial'] for m in members_a))}"
+        key_b = f"librenms-stack-{','.join(sorted(m['serial'] for m in members_b))}"
+        assert key_a != key_b
+
+
+class TestVirtualChassisEdgeBranches:
+    """Targeted tests for exception branches not covered by main tests."""
+
+    def test_detect_vc_invalid_position_string_falls_back(self):
+        """When entPhysicalParentRelPos is a non-numeric string, position falls back to idx+1."""
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.import_utils.virtual_chassis import detect_virtual_chassis_from_inventory
+
+        mock_api = MagicMock()
+        mock_api.get_device_info.return_value = (True, {"sysName": "sw1"})
+        mock_api.get_inventory_filtered.side_effect = [
+            (True, [{"entPhysicalClass": "stack", "entPhysicalIndex": 100}]),
+            (
+                True,
+                [
+                    {"entPhysicalClass": "chassis", "entPhysicalParentRelPos": "bad", "entPhysicalIndex": 201},
+                    {"entPhysicalClass": "chassis", "entPhysicalParentRelPos": "invalid", "entPhysicalIndex": 202},
+                ],
+            ),
+        ]
+
+        with patch(
+            "netbox_librenms_plugin.import_utils.virtual_chassis._load_vc_member_name_pattern",
+            return_value="-M{position}",
+        ):
+            result = detect_virtual_chassis_from_inventory(mock_api, 1)
+
+        # invalid string → idx+1 fallback (1-based: idx=0→1, idx=1→2)
+        positions = sorted(m["position"] for m in result["members"])
+        assert positions == [1, 2]
+
+    def test_update_vc_suggested_names_invalid_position_string_falls_back(self):
+        """Non-numeric position string in member triggers except branch → idx+1 fallback."""
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.import_utils.virtual_chassis import update_vc_member_suggested_names
+
+        vc_data = {
+            "is_stack": True,
+            "member_count": 2,
+            "members": [{"serial": "S1", "position": "bad"}, {"serial": "S2", "position": None}],
+        }
+
+        with patch(
+            "netbox_librenms_plugin.import_utils.virtual_chassis._load_vc_member_name_pattern",
+            return_value="-M{position}",
+        ):
+            result = update_vc_member_suggested_names(vc_data, "sw")
+
+        positions = [m["position"] for m in result["members"]]
+        assert positions[0] == 1  # idx=0 → 1
+        assert positions[1] == 2  # idx=1 → 2
+
+    def _make_atomic(self):
+        from contextlib import contextmanager
+
+        @contextmanager
+        def _atomic():
+            yield
+
+        return _atomic
+
+    def _base_patches(self):
+        from unittest.mock import patch
+
+        return [
+            patch(
+                "netbox_librenms_plugin.import_utils.virtual_chassis.transaction.atomic",
+                self._make_atomic(),
+            ),
+            patch(
+                "netbox_librenms_plugin.import_utils.virtual_chassis._load_vc_member_name_pattern",
+                return_value="-M{position}",
+            ),
+        ]
+
+    def test_create_vc_master_name_conflict_keeps_original(self):
+        """When the renamed master clashes, master_base_name stays as original."""
+        from contextlib import contextmanager
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.import_utils.virtual_chassis import create_virtual_chassis_with_members
+
+        master_device = MagicMock()
+        master_device.name = "sw1"
+        master_device.pk = 1
+        master_device.serial = ""
+        master_device.rack = None
+        master_device.location = None
+
+        mock_vc = MagicMock()
+        mock_vc.members.count.return_value = 1
+
+        @contextmanager
+        def mock_atomic():
+            yield
+
+        with (
+            patch(
+                "netbox_librenms_plugin.import_utils.virtual_chassis.transaction.atomic",
+                mock_atomic,
+            ),
+            patch(
+                "netbox_librenms_plugin.import_utils.virtual_chassis._generate_vc_member_name",
+                return_value="sw1-M1",
+            ),
+            patch("netbox_librenms_plugin.import_utils.virtual_chassis.Device") as mock_device_cls,
+            patch("netbox_librenms_plugin.import_utils.virtual_chassis.VirtualChassis") as mock_vc_cls,
+            patch(
+                "netbox_librenms_plugin.import_utils.virtual_chassis._load_vc_member_name_pattern",
+                return_value="-M{position}",
+            ),
+        ):
+            # Name conflict: renamed master already exists
+            mock_device_cls.objects.filter.return_value.exclude.return_value.exists.return_value = True
+            mock_vc_cls.objects.create.return_value = mock_vc
+
+            result = create_virtual_chassis_with_members(master_device, [], {"device_id": 1})
+
+        # VC still created; master.name was NOT changed (conflict)
+        assert result == mock_vc
+        assert master_device.name == "sw1"
+
+    def test_create_vc_member_serial_matches_master_skipped(self):
+        """Member whose serial equals master serial is skipped."""
+        from contextlib import contextmanager
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.import_utils.virtual_chassis import create_virtual_chassis_with_members
+
+        master_device = MagicMock()
+        master_device.name = "sw1"
+        master_device.pk = 1
+        master_device.serial = "SERIAL-MASTER"
+        master_device.rack = None
+        master_device.location = None
+
+        mock_vc = MagicMock()
+        mock_vc.members.count.return_value = 1
+
+        @contextmanager
+        def mock_atomic():
+            yield
+
+        with (
+            patch(
+                "netbox_librenms_plugin.import_utils.virtual_chassis.transaction.atomic",
+                mock_atomic,
+            ),
+            patch(
+                "netbox_librenms_plugin.import_utils.virtual_chassis._generate_vc_member_name",
+                return_value="sw1-M1",
+            ),
+            patch("netbox_librenms_plugin.import_utils.virtual_chassis.Device") as mock_device_cls,
+            patch("netbox_librenms_plugin.import_utils.virtual_chassis.VirtualChassis") as mock_vc_cls,
+            patch(
+                "netbox_librenms_plugin.import_utils.virtual_chassis._load_vc_member_name_pattern",
+                return_value="-M{position}",
+            ),
+        ):
+            mock_device_cls.objects.filter.return_value.exclude.return_value.exists.return_value = False
+            mock_device_cls.objects.filter.return_value.exists.return_value = False
+            mock_vc_cls.objects.create.return_value = mock_vc
+
+            # One member with same serial as master → should be skipped
+            members_info = [{"serial": "SERIAL-MASTER", "position": 2, "name": "sw1-2"}]
+            create_virtual_chassis_with_members(master_device, members_info, {"device_id": 1})
+
+        # Device.objects.create should NOT be called (member skipped)
+        mock_device_cls.objects.create.assert_not_called()
+
+    def test_create_vc_member_duplicate_serial_skipped(self):
+        """Member with a serial that already exists in DB is skipped."""
+        from contextlib import contextmanager
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.import_utils.virtual_chassis import create_virtual_chassis_with_members
+
+        master_device = MagicMock()
+        master_device.name = "sw1"
+        master_device.pk = 1
+        master_device.serial = ""
+        master_device.rack = None
+        master_device.location = None
+
+        mock_vc = MagicMock()
+        mock_vc.members.count.return_value = 1
+
+        @contextmanager
+        def mock_atomic():
+            yield
+
+        def _filter_exists(*args, **kwargs):
+            # First call: check renamed master name conflict (exclude().exists()) → False
+            # Subsequent calls: check duplicate serial → True (for serial)
+            mock = MagicMock()
+            mock.exclude.return_value.exists.return_value = False
+            mock.exists.return_value = True  # serial already exists
+            return mock
+
+        with (
+            patch(
+                "netbox_librenms_plugin.import_utils.virtual_chassis.transaction.atomic",
+                mock_atomic,
+            ),
+            patch(
+                "netbox_librenms_plugin.import_utils.virtual_chassis._generate_vc_member_name",
+                return_value="sw1-M2",
+            ),
+            patch("netbox_librenms_plugin.import_utils.virtual_chassis.Device") as mock_device_cls,
+            patch("netbox_librenms_plugin.import_utils.virtual_chassis.VirtualChassis") as mock_vc_cls,
+            patch(
+                "netbox_librenms_plugin.import_utils.virtual_chassis._load_vc_member_name_pattern",
+                return_value="-M{position}",
+            ),
+        ):
+            mock_device_cls.objects.filter.side_effect = _filter_exists
+            mock_vc_cls.objects.create.return_value = mock_vc
+
+            members_info = [{"serial": "DUP-SERIAL", "position": 2, "name": "sw1-2"}]
+            create_virtual_chassis_with_members(master_device, members_info, {"device_id": 1})
+
+        mock_device_cls.objects.create.assert_not_called()
+
+    def test_create_vc_member_created_successfully(self):
+        """Normal member (no duplicate serial/name) is created via Device.objects.create."""
+        from contextlib import contextmanager
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.import_utils.virtual_chassis import create_virtual_chassis_with_members
+
+        master_device = MagicMock()
+        master_device.name = "sw1"
+        master_device.pk = 1
+        master_device.serial = ""
+        master_device.rack = None
+        master_device.location = None
+        master_device.platform = None
+        master_device.role = MagicMock()
+        master_device.device_type = MagicMock()
+        master_device.site = MagicMock()
+
+        mock_vc = MagicMock()
+        mock_vc.members.count.return_value = 2
+
+        @contextmanager
+        def mock_atomic():
+            yield
+
+        def _filter_side_effect(*args, **kwargs):
+            mock = MagicMock()
+            mock.exclude.return_value.exists.return_value = False  # no name conflict
+            mock.exists.return_value = False  # no duplicate serial or name
+            return mock
+
+        with (
+            patch(
+                "netbox_librenms_plugin.import_utils.virtual_chassis.transaction.atomic",
+                mock_atomic,
+            ),
+            patch(
+                "netbox_librenms_plugin.import_utils.virtual_chassis._generate_vc_member_name",
+                return_value="sw1-M2",
+            ),
+            patch("netbox_librenms_plugin.import_utils.virtual_chassis.Device") as mock_device_cls,
+            patch("netbox_librenms_plugin.import_utils.virtual_chassis.VirtualChassis") as mock_vc_cls,
+            patch(
+                "netbox_librenms_plugin.import_utils.virtual_chassis._load_vc_member_name_pattern",
+                return_value="-M{position}",
+            ),
+        ):
+            mock_device_cls.objects.filter.side_effect = _filter_side_effect
+            mock_vc_cls.objects.create.return_value = mock_vc
+
+            members_info = [{"serial": "NEW-SERIAL", "position": 2, "name": "sw1-2"}]
+            result = create_virtual_chassis_with_members(master_device, members_info, {"device_id": 1})
+
+        mock_device_cls.objects.create.assert_called_once()
+        assert result == mock_vc
+
+    def test_create_vc_member_count_warning_when_fewer_created(self):
+        """Warning is logged when members_created < expected_members."""
+        from contextlib import contextmanager
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.import_utils.virtual_chassis import create_virtual_chassis_with_members
+
+        master_device = MagicMock()
+        master_device.name = "sw1"
+        master_device.pk = 1
+        master_device.serial = ""
+        master_device.rack = None
+        master_device.location = None
+
+        mock_vc = MagicMock()
+        mock_vc.members.count.return_value = 1
+
+        @contextmanager
+        def mock_atomic():
+            yield
+
+        def _filter_side_effect(*args, **kwargs):
+            mock = MagicMock()
+            mock.exclude.return_value.exists.return_value = False
+            # serial check: True → member skipped
+            mock.exists.return_value = True
+            return mock
+
+        with (
+            patch(
+                "netbox_librenms_plugin.import_utils.virtual_chassis.transaction.atomic",
+                mock_atomic,
+            ),
+            patch(
+                "netbox_librenms_plugin.import_utils.virtual_chassis._generate_vc_member_name",
+                return_value="sw1-M2",
+            ),
+            patch("netbox_librenms_plugin.import_utils.virtual_chassis.Device") as mock_device_cls,
+            patch("netbox_librenms_plugin.import_utils.virtual_chassis.VirtualChassis") as mock_vc_cls,
+            patch(
+                "netbox_librenms_plugin.import_utils.virtual_chassis._load_vc_member_name_pattern",
+                return_value="-M{position}",
+            ),
+            patch("netbox_librenms_plugin.import_utils.virtual_chassis.logger") as mock_logger,
+        ):
+            mock_device_cls.objects.filter.side_effect = _filter_side_effect
+            mock_vc_cls.objects.create.return_value = mock_vc
+
+            # 2 members expected, both skipped → warning
+            members_info = [
+                {"serial": "S1", "position": 2, "name": "sw1-2"},
+                {"serial": "S2", "position": 3, "name": "sw1-3"},
+            ]
+            create_virtual_chassis_with_members(master_device, members_info, {"device_id": 1})
+
+        # Warning should be called for count mismatch
+        mock_logger.warning.assert_called()
+
+    def test_create_vc_member_zero_position_and_name_conflict(self):
+        """Member position=0 → discovered_pos=None, and name conflict → skip."""
+        from contextlib import contextmanager
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.import_utils.virtual_chassis import create_virtual_chassis_with_members
+
+        master_device = MagicMock()
+        master_device.name = "sw1"
+        master_device.pk = 1
+        master_device.serial = ""
+        master_device.rack = None
+        master_device.location = None
+        master_device.platform = None
+        master_device.role = MagicMock()
+        master_device.device_type = MagicMock()
+        master_device.site = MagicMock()
+
+        mock_vc = MagicMock()
+        mock_vc.members.count.return_value = 1
+
+        @contextmanager
+        def mock_atomic():
+            yield
+
+        filter_call_count = [0]
+
+        def _filter_side_effect(*args, **kwargs):
+            mock = MagicMock()
+            mock.exclude.return_value.exists.return_value = False  # no renamed-master conflict
+            filter_call_count[0] += 1
+            # call 1: renamed-master name conflict check (.exclude().exists()) → handled above
+            # call 2: serial duplicate check (.exists()) → False (serial doesn't exist)
+            # call 3: member name conflict check (.exists()) → True (name already taken)
+            mock.exists.return_value = filter_call_count[0] == 3
+            return mock
+
+        with (
+            patch(
+                "netbox_librenms_plugin.import_utils.virtual_chassis.transaction.atomic",
+                mock_atomic,
+            ),
+            patch(
+                "netbox_librenms_plugin.import_utils.virtual_chassis._generate_vc_member_name",
+                return_value="sw1-M2",
+            ),
+            patch("netbox_librenms_plugin.import_utils.virtual_chassis.Device") as mock_device_cls,
+            patch("netbox_librenms_plugin.import_utils.virtual_chassis.VirtualChassis") as mock_vc_cls,
+            patch(
+                "netbox_librenms_plugin.import_utils.virtual_chassis._load_vc_member_name_pattern",
+                return_value="-M{position}",
+            ),
+        ):
+            mock_device_cls.objects.filter.side_effect = _filter_side_effect
+            mock_vc_cls.objects.create.return_value = mock_vc
+
+            # position=0 → discovered_pos normalized to None; serial present but name conflicts
+            members_info = [{"serial": "S-UNIQUE", "position": 0, "name": "sw1-2"}]
+            create_virtual_chassis_with_members(master_device, members_info, {"device_id": 1})
+
+        # Member skipped due to name conflict (not created)
+        mock_device_cls.objects.create.assert_not_called()
+
+    def test_create_vc_member_invalid_position_string_uses_sequential(self):
+        """Member with position='abc' (non-int) triggers except branch → uses sequential counter."""
+        from contextlib import contextmanager
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.import_utils.virtual_chassis import create_virtual_chassis_with_members
+
+        master_device = MagicMock()
+        master_device.name = "sw1"
+        master_device.pk = 1
+        master_device.serial = ""
+        master_device.rack = None
+        master_device.location = None
+        master_device.platform = None
+        master_device.role = MagicMock()
+        master_device.device_type = MagicMock()
+        master_device.site = MagicMock()
+
+        mock_vc = MagicMock()
+        mock_vc.members.count.return_value = 2
+
+        created_positions = []
+
+        @contextmanager
+        def mock_atomic():
+            yield
+
+        def _filter_side_effect(*args, **kwargs):
+            mock = MagicMock()
+            mock.exclude.return_value.exists.return_value = False
+            mock.exists.return_value = False
+            return mock
+
+        def _capture_create(**kwargs):
+            created_positions.append(kwargs.get("vc_position"))
+            return MagicMock()
+
+        with (
+            patch(
+                "netbox_librenms_plugin.import_utils.virtual_chassis.transaction.atomic",
+                mock_atomic,
+            ),
+            patch(
+                "netbox_librenms_plugin.import_utils.virtual_chassis._generate_vc_member_name",
+                return_value="sw1-M2",
+            ),
+            patch("netbox_librenms_plugin.import_utils.virtual_chassis.Device") as mock_device_cls,
+            patch("netbox_librenms_plugin.import_utils.virtual_chassis.VirtualChassis") as mock_vc_cls,
+            patch(
+                "netbox_librenms_plugin.import_utils.virtual_chassis._load_vc_member_name_pattern",
+                return_value="-M{position}",
+            ),
+        ):
+            mock_device_cls.objects.filter.side_effect = _filter_side_effect
+            mock_device_cls.objects.create.side_effect = _capture_create
+            mock_vc_cls.objects.create.return_value = mock_vc
+
+            # "abc" position → except branch → sequential fallback (position=2, then +=1)
+            members_info = [{"serial": "S1", "position": "abc", "name": "m1"}]
+            create_virtual_chassis_with_members(master_device, members_info, {"device_id": 1})
+
+        assert mock_device_cls.objects.create.call_count == 1
diff --git a/netbox_librenms_plugin/tests/test_integration_sync.py b/netbox_librenms_plugin/tests/test_integration_sync.py
index 477c423fb4..b7eb266868 100644
--- a/netbox_librenms_plugin/tests/test_integration_sync.py
+++ b/netbox_librenms_plugin/tests/test_integration_sync.py
@@ -347,3 +347,51 @@ def test_get_librenms_id_falls_back_to_hostname_when_ip_fails(self, mock_server)
                     result = api.get_librenms_id(obj)
 
         assert result == 42
+
+
+class TestLibreNMSAPIErrorResponses:
+    """Integration tests: API client handles unusual server responses gracefully."""
+
+    def test_401_returns_false(self, mock_server):
+        """HTTP 401 Unauthorized must return (False, ...) not raise."""
+        api = _make_api(mock_server.url)
+        mock_server.register("/api/v0/devices", {"message": "Unauthorized"}, status=401)
+        success, data = api.list_devices()
+        assert success is False
+
+    def test_500_returns_false(self, mock_server):
+        """HTTP 500 must return (False, ...) not raise."""
+        api = _make_api(mock_server.url)
+        mock_server.register("/api/v0/devices", {"message": "Internal error"}, status=500)
+        success, data = api.list_devices()
+        assert success is False
+
+    def test_null_inventory_returns_false(self, mock_server):
+        """{"status":"ok","inventory":null} must not raise, must return (False, ...)."""
+        api = _make_api(mock_server.url)
+        mock_server.register("/api/v0/devices/1/inventory", {"status": "ok", "inventory": None})
+        success, data = api.get_device_inventory(1)
+        assert success is False
+
+    def test_null_devices_field_get_device_info(self, mock_server):
+        """{"devices": null} in get_device_info must return (False, None) not crash."""
+        api = _make_api(mock_server.url)
+        mock_server.register("/api/v0/devices/42", {"devices": None})
+        success, data = api.get_device_info(42)
+        assert success is False
+        assert data is None
+
+    def test_empty_devices_list_get_device_info(self, mock_server):
+        """{"devices": []} in get_device_info must return (False, None)."""
+        api = _make_api(mock_server.url)
+        mock_server.register("/api/v0/devices/42", {"devices": []})
+        success, data = api.get_device_info(42)
+        assert success is False
+
+    def test_404_get_device_info(self, mock_server):
+        """404 on device endpoint must return (False, None)."""
+        api = _make_api(mock_server.url)
+        mock_server.register("/api/v0/devices/99", {"message": "Device not found"}, status=404)
+        success, data = api.get_device_info(99)
+        assert success is False
+        assert data is None
diff --git a/netbox_librenms_plugin/tests/test_librenms_api.py b/netbox_librenms_plugin/tests/test_librenms_api.py
index 2a7bd41630..5a00a0225a 100644
--- a/netbox_librenms_plugin/tests/test_librenms_api.py
+++ b/netbox_librenms_plugin/tests/test_librenms_api.py
@@ -473,7 +473,7 @@ def test_get_librenms_id_from_custom_field(self, mock_librenms_config):
         assert result == 42
 
     def test_get_librenms_id_normalizes_string_to_int(self, mock_librenms_config):
-        """Converts a string-stored librenms_id to int and writes it back."""
+        """Returns int for string-stored librenms_id; read path uses auto_save=False so no write-back."""
         from netbox_librenms_plugin.librenms_api import LibreNMSAPI
 
         api = LibreNMSAPI(server_key="default")
@@ -485,9 +485,8 @@ def test_get_librenms_id_normalizes_string_to_int(self, mock_librenms_config):
 
         result = api.get_librenms_id(device)
         assert result == 42
-        # normalized value written back
-        assert device.custom_field_data["librenms_id"] == 42
-        device.save.assert_called_once()
+        # auto_save=False in this read path — normalization is NOT written back
+        device.save.assert_not_called()
 
     def test_get_librenms_id_empty_string_falls_through_to_discovery(self, mock_librenms_config):
         """An empty-string librenms_id is treated as not set (falls through to API discovery)."""
@@ -774,7 +773,7 @@ def test_get_device_info_success(self, mock_get, mock_librenms_config):
 
     @patch("netbox_librenms_plugin.librenms_api.requests.get")
     def test_get_device_info_not_found(self, mock_get, mock_librenms_config):
-        """Verify handling of getting non-existent device."""
+        """Empty devices list returns (False, None) without raising."""
         mock_get.return_value.status_code = 200
         mock_get.return_value.json.return_value = {"status": "ok", "devices": []}
 
@@ -782,9 +781,9 @@ def test_get_device_info_not_found(self, mock_get, mock_librenms_config):
 
         api = LibreNMSAPI(server_key="default")
 
-        # Should raise IndexError when devices list is empty
-        with pytest.raises(IndexError):
-            api.get_device_info(device_id=999)
+        success, result = api.get_device_info(1)
+        assert success is False
+        assert result is None
 
     @patch("netbox_librenms_plugin.librenms_api.requests.get")
     def test_list_devices_with_filters(self, mock_get, mock_librenms_config):
@@ -1237,3 +1236,111 @@ def test_ssl_verification_error(self, mock_get, mock_librenms_config):
 # Test Class 5-9 continuing in next part due to length...
 # Run `make unittest` to execute all tests
 # ====================================================================================
+
+
+# ====================================================================================
+# Guard tests: int conversion guard and VLAN dict guard
+# ====================================================================================
+
+
+class TestGetLibreNMSIdIntGuard:
+    """Tests for the int conversion guard in get_librenms_id."""
+
+    def test_non_integer_string_from_ip_returns_none(self, mock_librenms_config):
+        """When get_device_id_by_ip returns a non-int string, _store_librenms_id must not be called."""
+        from unittest.mock import MagicMock, patch
+
+        from netbox_librenms_plugin.librenms_api import LibreNMSAPI
+
+        api = LibreNMSAPI(server_key="default")
+
+        obj = MagicMock()
+        obj.primary_ip.address.ip = "192.168.1.1"
+        obj.primary_ip.dns_name = ""
+        obj.name = "test-device"
+        obj._meta.model_name = "device"
+        obj.pk = 1
+
+        with (
+            patch.object(api, "_get_cache_key", return_value="test_cache_key"),
+            patch("netbox_librenms_plugin.librenms_api.cache") as mock_cache,
+            patch.object(api, "get_device_id_by_ip", return_value="not-an-int"),
+            patch.object(api, "get_device_id_by_hostname", return_value=None),
+            patch.object(api, "_store_librenms_id") as mock_store,
+        ):
+            mock_cache.get.return_value = None
+            result = api.get_librenms_id(obj)
+
+        assert result is None
+        mock_store.assert_not_called()
+
+    def test_valid_integer_string_stores_and_returns(self, mock_librenms_config):
+        """When get_device_id_by_ip returns a valid int string, it should be stored and returned."""
+        from unittest.mock import MagicMock, patch
+
+        from netbox_librenms_plugin.librenms_api import LibreNMSAPI
+
+        api = LibreNMSAPI(server_key="default")
+
+        obj = MagicMock()
+        obj.primary_ip.address.ip = "192.168.1.1"
+        obj.primary_ip.dns_name = ""
+        obj.name = "test-device"
+        obj._meta.model_name = "device"
+        obj.pk = 1
+
+        with (
+            patch.object(api, "_get_cache_key", return_value="test_cache_key"),
+            patch("netbox_librenms_plugin.librenms_api.cache") as mock_cache,
+            patch.object(api, "get_device_id_by_ip", return_value="42"),
+            patch.object(api, "_store_librenms_id") as mock_store,
+        ):
+            mock_cache.get.return_value = None
+            result = api.get_librenms_id(obj)
+
+        assert result == 42
+        mock_store.assert_called_once_with(obj, 42)
+
+
+class TestVlanEntryDictGuard:
+    """Tests for the isinstance(vlan_entry, dict) guard in _parse_port_vlan_info."""
+
+    def test_non_dict_entry_is_skipped(self, mock_librenms_config):
+        """Non-dict entries in vlans_data should be skipped without error."""
+        from netbox_librenms_plugin.librenms_api import LibreNMSAPI
+
+        api = LibreNMSAPI(server_key="default")
+
+        port_data = {
+            "ifName": "eth0",
+            "ifDescr": "eth0",
+            "port_id": 1,
+            "ifTrunk": "dot1Q",
+            "ifVlan": None,
+            "vlans": [{"vlan": 10, "untagged": 1}, "bad_entry", {"vlan": 20}],
+        }
+        result = api.parse_port_vlan_data(port_data)
+
+        # Only VIDs 10 and 20 should be parsed; string entry is skipped
+        assert result["untagged_vlan"] == 10
+        assert 20 in result["tagged_vlans"]
+        assert len(result["tagged_vlans"]) == 1
+
+    def test_mixed_bad_entries_no_exception(self, mock_librenms_config):
+        """Multiple non-dict entries mixed with valid dicts should not raise."""
+        from netbox_librenms_plugin.librenms_api import LibreNMSAPI
+
+        api = LibreNMSAPI(server_key="default")
+
+        port_data = {
+            "ifName": "eth0",
+            "ifDescr": "eth0",
+            "port_id": 2,
+            "ifTrunk": "dot1Q",
+            "ifVlan": None,
+            "vlans": [None, 123, "unexpected", {"vlan": 30}],
+        }
+        result = api.parse_port_vlan_data(port_data)
+
+        assert result["tagged_vlans"] == [30]
+        assert result["untagged_vlan"] is None
diff --git a/netbox_librenms_plugin/tests/test_librenms_id.py b/netbox_librenms_plugin/tests/test_librenms_id.py
new file mode 100644
index 0000000000..9e53337af5
--- /dev/null
+++ b/netbox_librenms_plugin/tests/test_librenms_id.py
@@ -0,0 +1,505 @@
+"""
+Tests for multi-server librenms_id helpers.
+
+Covers get_librenms_device_id, set_librenms_device_id, find_by_librenms_id,
+and migrate_legacy_librenms_id.
+"""
+
+from unittest.mock import MagicMock
+
+
+class TestGetLibreNMSDeviceId:
+    """Tests for get_librenms_device_id()."""
+
+    def test_returns_none_when_cf_missing(self):
+        from netbox_librenms_plugin.utils import get_librenms_device_id
+
+        obj = MagicMock()
+        obj.cf = {}
+        result = get_librenms_device_id(obj, "default")
+        assert result is None
+
+    def test_returns_int_for_legacy_bare_integer(self):
+        from netbox_librenms_plugin.utils import get_librenms_device_id
+
+        obj = MagicMock()
+        obj.cf = {"librenms_id": 42}
+        result = get_librenms_device_id(obj, "default")
+        assert result == 42
+
+    def test_legacy_bare_int_returned_for_any_server_key(self):
+        """
+        Legacy bare integers are returned as a universal fallback for any server_key.
+
+        Devices imported before multi-server support store a bare integer in
+        librenms_id.  These must remain discoverable regardless of which server is
+        active, so the bare-int is returned as-is for any server_key.
+        """
+        from netbox_librenms_plugin.utils import get_librenms_device_id
+
+        obj = MagicMock()
+        obj.cf = {"librenms_id": 99}
+        assert get_librenms_device_id(obj, "default") == 99
+        assert get_librenms_device_id(obj, "production") == 99
+        assert get_librenms_device_id(obj, "secondary") == 99
+
+    def test_returns_value_for_matching_server_key(self):
+        from netbox_librenms_plugin.utils import get_librenms_device_id
+
+        obj = MagicMock()
+        obj.cf = {"librenms_id": {"production": 7, "secondary": 12}}
+        assert get_librenms_device_id(obj, "production") == 7
+
+    def test_returns_none_for_missing_server_key_in_dict(self):
+        from netbox_librenms_plugin.utils import get_librenms_device_id
+
+        obj = MagicMock()
+        obj.cf = {"librenms_id": {"production": 7}}
+        result = get_librenms_device_id(obj, "secondary")
+        assert result is None
+
+    def test_returns_none_for_unexpected_type(self):
+        from netbox_librenms_plugin.utils import get_librenms_device_id
+
+        obj = MagicMock()
+        obj.cf = {"librenms_id": "not-an-int-or-dict"}
+        result = get_librenms_device_id(obj, "default")
+        assert result is None
+
+    def test_legacy_string_int_returned_for_any_server_key(self):
+        """A bare string integer ('42') is coerced and returned for any server_key."""
+        from netbox_librenms_plugin.utils import get_librenms_device_id
+
+        obj = MagicMock()
+        obj.cf = {"librenms_id": "42"}
+        assert get_librenms_device_id(obj, "default") == 42
+        assert get_librenms_device_id(obj, "production") == 42
+
+    def test_returns_none_for_bare_boolean(self):
+        """bool is a subclass of int; bare True/False must not be treated as a valid ID."""
+        from netbox_librenms_plugin.utils import get_librenms_device_id
+
+        obj = MagicMock()
+        obj.cf = {"librenms_id": True}
+        assert get_librenms_device_id(obj, "default") is None
+
+        obj.cf = {"librenms_id": False}
+        assert get_librenms_device_id(obj, "default") is None
+
+    def test_returns_none_for_boolean_inside_dict(self):
+        """Boolean values inside the JSON dict must be rejected."""
+        from netbox_librenms_plugin.utils import get_librenms_device_id
+
+        obj = MagicMock()
+        obj.cf = {"librenms_id": {"default": True}}
+        assert get_librenms_device_id(obj, "default") is None
+
+    def test_default_server_key_is_default(self):
+        from netbox_librenms_plugin.utils import get_librenms_device_id
+
+        obj = MagicMock()
+        obj.cf = {"librenms_id": {"default": 5}}
+        assert get_librenms_device_id(obj) == 5
+
+
+class TestGetLibreNMSDeviceIdAutoSave:
+    """Tests for auto_save behaviour of get_librenms_device_id()."""
+
+    def test_auto_save_true_mutates_bare_string(self):
+        """When auto_save=True (default), a bare string is normalised in-place and saved."""
+        from netbox_librenms_plugin.utils import get_librenms_device_id
+
+        obj = MagicMock()
+        obj.cf = {"librenms_id": "42"}
+        obj.custom_field_data = {"librenms_id": "42"}
+        result = get_librenms_device_id(obj, "default", auto_save=True)
+        assert result == 42
+        assert obj.custom_field_data["librenms_id"] == 42
+        obj.save.assert_called_once()
+
+    def test_auto_save_false_does_not_mutate_bare_string(self):
+        """When auto_save=False, bare string is returned as int but obj is not mutated."""
+        from netbox_librenms_plugin.utils import get_librenms_device_id
+
+        obj = MagicMock()
+        obj.cf = {"librenms_id": "42"}
+        obj.custom_field_data = {"librenms_id": "42"}
+        result = get_librenms_device_id(obj, "default", auto_save=False)
+        assert result == 42
+        assert obj.custom_field_data["librenms_id"] == "42"
+        obj.save.assert_not_called()
+
+    def test_auto_save_false_does_not_mutate_string_in_dict(self):
+        """When auto_save=False, string inside dict is returned as int but dict is not mutated."""
+        from netbox_librenms_plugin.utils import get_librenms_device_id
+
+        obj = MagicMock()
+        obj.cf = {"librenms_id": {"prod": "7"}}
+        obj.custom_field_data = {"librenms_id": {"prod": "7"}}
+        result = get_librenms_device_id(obj, "prod", auto_save=False)
+        assert result == 7
+        assert obj.custom_field_data["librenms_id"]["prod"] == "7"
+        obj.save.assert_not_called()
+
+    def test_auto_save_true_mutates_string_in_dict(self):
+        """When auto_save=True, string inside dict is normalised and saved."""
+        from netbox_librenms_plugin.utils import get_librenms_device_id
+
+        obj = MagicMock()
+        obj.cf = {"librenms_id": {"prod": "7"}}
+        obj.custom_field_data = {"librenms_id": {"prod": "7"}}
+        result = get_librenms_device_id(obj, "prod", auto_save=True)
+        assert result == 7
+        assert obj.custom_field_data["librenms_id"]["prod"] == 7
+        obj.save.assert_called_once()
+
+
+class TestFindByLibreNMSId:
+    """Tests for find_by_librenms_id()."""
+
+    def test_rejects_boolean_true(self):
+        """find_by_librenms_id(model, True) returns None without querying."""
+        from netbox_librenms_plugin.utils import find_by_librenms_id
+
+        mock_model = MagicMock()
+        result = find_by_librenms_id(mock_model, True, "default")
+        assert result is None
+        mock_model.objects.filter.assert_not_called()
+
+    def test_rejects_boolean_false(self):
+        """find_by_librenms_id(model, False) returns None without querying."""
+        from netbox_librenms_plugin.utils import find_by_librenms_id
+
+        mock_model = MagicMock()
+        result = find_by_librenms_id(mock_model, False, "default")
+        assert result is None
+        mock_model.objects.filter.assert_not_called()
+
+    def test_queries_server_key_and_legacy_integer(self):
+        """
+        find_by_librenms_id() issues a Q that covers both the JSON server-key branch
+        and the legacy bare-int branch in a single filter() call.
+
+        We inspect the Q object's children directly because the two branches must
+        coexist — matching only one would silently miss devices stored in the other
+        format.
+        """
+        from unittest.mock import MagicMock
+        from django.db.models import Q
+        from netbox_librenms_plugin.utils import find_by_librenms_id
+
+        mock_model = MagicMock()
+        mock_qs = MagicMock()
+        mock_model.objects.filter.return_value = mock_qs
+        mock_qs.first.return_value = None
+
+        find_by_librenms_id(mock_model, 42, "default")
+
+        mock_model.objects.filter.assert_called_once()
+        # Verify the Q predicate covers both the server-key JSON branch and legacy bare-int/string branches
+        call_args = mock_model.objects.filter.call_args
+        q_arg = call_args[0][0]
+        assert isinstance(q_arg, Q)
+        assert q_arg.connector == "OR"
+        # The combined Q should contain four children: JSON key (int), JSON key (str), bare-int, bare-string
+        q_str = str(q_arg)
+        assert "librenms_id__default" in q_str
+        assert "custom_field_data__librenms_id__default" in q_str
+        assert "custom_field_data__librenms_id" in q_str
+        assert "42" in q_str
+
+    def test_returns_first_matching_object(self):
+        from netbox_librenms_plugin.utils import find_by_librenms_id
+
+        expected = MagicMock()
+        mock_model = MagicMock()
+        mock_qs = MagicMock()
+        mock_model.objects.filter.return_value = mock_qs
+        mock_qs.first.return_value = expected
+
+        result = find_by_librenms_id(mock_model, 42, "default")
+        assert result is expected
+
+    def test_returns_none_when_not_found(self):
+        from unittest.mock import MagicMock
+        from django.db.models import Q
+        from netbox_librenms_plugin.utils import find_by_librenms_id
+
+        mock_model = MagicMock()
+        mock_qs = MagicMock()
+        mock_model.objects.filter.return_value = mock_qs
+        mock_qs.first.return_value = None
+
+        result = find_by_librenms_id(mock_model, 999, "production")
+        assert result is None
+
+        # Any server_key must include legacy bare-int/string fallback conditions
+        # so that devices imported before multi-server support are still found.
+        call_args = mock_model.objects.filter.call_args
+        q_arg = call_args[0][0]
+        assert isinstance(q_arg, Q)
+        q_str = str(q_arg)
+        assert "custom_field_data__librenms_id__production" in q_str
+        assert "custom_field_data__librenms_id" in q_str
+
+    def test_default_server_key_is_default(self):
+        from netbox_librenms_plugin.utils import find_by_librenms_id
+        from django.db.models import Q
+
+        mock_model = MagicMock()
+        mock_qs = MagicMock()
+        mock_model.objects.filter.return_value = mock_qs
+        mock_qs.first.return_value = None
+
+        find_by_librenms_id(mock_model, 42)
+
+        # Verify the Q predicate uses "default" server key — not an arbitrary key
+        mock_model.objects.filter.assert_called_once()
+        call_args = mock_model.objects.filter.call_args
+        q_arg = call_args[0][0]
+        assert isinstance(q_arg, Q)
+        assert q_arg.connector == "OR"
+        q_str = str(q_arg)
+        assert "custom_field_data__librenms_id__default" in q_str
+
+
+class TestMigrateLegacyLibreNMSId:
+    """Tests for migrate_legacy_librenms_id()."""
+
+    def test_returns_true_when_migrated(self):
+        from netbox_librenms_plugin.utils import migrate_legacy_librenms_id
+
+        obj = MagicMock()
+        obj.custom_field_data = {"librenms_id": 42}
+        result = migrate_legacy_librenms_id(obj, "default")
+        assert result is True
+
+    def test_migrates_integer_to_dict_format(self):
+        from netbox_librenms_plugin.utils import migrate_legacy_librenms_id
+
+        obj = MagicMock()
+        obj.custom_field_data = {"librenms_id": 42}
+        migrate_legacy_librenms_id(obj, "production")
+        assert obj.custom_field_data["librenms_id"] == {"production": 42}
+
+    def test_migrates_string_digit_legacy_id(self):
+        """A string-digit like "42" should be migrated to {server_key: 42} (int)."""
+        from netbox_librenms_plugin.utils import migrate_legacy_librenms_id
+
+        obj = MagicMock()
+        obj.custom_field_data = {"librenms_id": "42"}
+        result = migrate_legacy_librenms_id(obj, "production")
+        assert result is True
+        assert obj.custom_field_data["librenms_id"] == {"production": 42}
+        assert isinstance(obj.custom_field_data["librenms_id"]["production"], int)
+        obj.save.assert_not_called()
+
+    def test_returns_false_for_non_digit_string(self):
+        """A non-digit string should not be migrated."""
+        from netbox_librenms_plugin.utils import migrate_legacy_librenms_id
+
+        obj = MagicMock()
+        obj.custom_field_data = {"librenms_id": "not-a-number"}
+        result = migrate_legacy_librenms_id(obj, "default")
+        assert result is False
+        assert obj.custom_field_data["librenms_id"] == "not-a-number"
+
+    def test_returns_false_for_plus_prefix_string(self):
+        """'+42' is not strictly digit-only; must not be migrated."""
+        from netbox_librenms_plugin.utils import migrate_legacy_librenms_id
+
+        obj = MagicMock()
+        obj.custom_field_data = {"librenms_id": "+42"}
+        result = migrate_legacy_librenms_id(obj, "default")
+        assert result is False
+        assert obj.custom_field_data["librenms_id"] == "+42"
+        obj.save.assert_not_called()
+
+    def test_returns_false_for_space_padded_string(self):
+        """' 42 ' is not strictly digit-only; must not be migrated."""
+        from netbox_librenms_plugin.utils import migrate_legacy_librenms_id
+
+        obj = MagicMock()
+        obj.custom_field_data = {"librenms_id": " 42 "}
+        result = migrate_legacy_librenms_id(obj, "default")
+        assert result is False
+        assert obj.custom_field_data["librenms_id"] == " 42 "
+        obj.save.assert_not_called()
+
+    def test_returns_false_when_already_dict(self):
+        from netbox_librenms_plugin.utils import migrate_legacy_librenms_id
+
+        obj = MagicMock()
+        obj.custom_field_data = {"librenms_id": {"default": 42}}
+        result = migrate_legacy_librenms_id(obj, "default")
+        assert result is False
+
+    def test_returns_false_when_value_is_none(self):
+        from netbox_librenms_plugin.utils import migrate_legacy_librenms_id
+
+        obj = MagicMock()
+        obj.custom_field_data = {"librenms_id": None}
+        result = migrate_legacy_librenms_id(obj, "default")
+        assert result is False
+
+    def test_returns_false_for_boolean_value(self):
+        """bool is a subclass of int; True/False must not be migrated."""
+        from netbox_librenms_plugin.utils import migrate_legacy_librenms_id
+
+        obj = MagicMock()
+        obj.custom_field_data = {"librenms_id": True}
+        assert migrate_legacy_librenms_id(obj, "default") is False
+        assert obj.custom_field_data["librenms_id"] is True  # unchanged
+
+    def test_does_not_call_save(self):
+        """migrate_legacy_librenms_id must NOT call obj.save() — caller is responsible."""
+        from netbox_librenms_plugin.utils import migrate_legacy_librenms_id
+
+        obj = MagicMock()
+        obj.custom_field_data = {"librenms_id": 7}
+        migrate_legacy_librenms_id(obj, "default")
+        obj.save.assert_not_called()
+
+    def test_preserves_value_in_migrated_dict(self):
+        from netbox_librenms_plugin.utils import migrate_legacy_librenms_id
+
+        obj = MagicMock()
+        obj.custom_field_data = {"librenms_id": 99}
+        migrate_legacy_librenms_id(obj, "secondary")
+        assert obj.custom_field_data["librenms_id"]["secondary"] == 99
+
+
+class TestLibreNMSIdRoundtrip:
+    """get_librenms_device_id should see the value set by set_librenms_device_id."""
+
+    def test_set_then_get_returns_same_value(self):
+        from netbox_librenms_plugin.utils import get_librenms_device_id, set_librenms_device_id
+
+        obj = MagicMock()
+        obj.custom_field_data = {}
+        obj.cf = obj.custom_field_data  # make cf a live view of custom_field_data
+
+        set_librenms_device_id(obj, 42, "production")
+        result = get_librenms_device_id(obj, "production")
+        assert result == 42
+
+    def test_set_multiple_servers_get_correct_each(self):
+        from netbox_librenms_plugin.utils import get_librenms_device_id, set_librenms_device_id
+
+        obj = MagicMock()
+        obj.custom_field_data = {}
+        obj.cf = obj.custom_field_data
+
+        set_librenms_device_id(obj, 10, "primary")
+        set_librenms_device_id(obj, 20, "secondary")
+
+        assert get_librenms_device_id(obj, "primary") == 10
+        assert get_librenms_device_id(obj, "secondary") == 20
+
+    def test_migrate_then_get_returns_value(self):
+        from netbox_librenms_plugin.utils import get_librenms_device_id, migrate_legacy_librenms_id
+
+        obj = MagicMock()
+        obj.custom_field_data = {"librenms_id": 55}
+        obj.cf = obj.custom_field_data
+
+        migrate_legacy_librenms_id(obj, "default")
+        result = get_librenms_device_id(obj, "default")
+        assert result == 55
+
+
+class TestSetLibreNMSDeviceId:
+    """Tests for set_librenms_device_id in utils.py."""
+
+    def test_stores_int_for_valid_device_id(self):
+        """Valid integer device_id is stored under server_key."""
+        from netbox_librenms_plugin.utils import set_librenms_device_id
+
+        obj = MagicMock()
+        obj.custom_field_data = {"librenms_id": None}
+        set_librenms_device_id(obj, 42, server_key="primary")
+        assert obj.custom_field_data["librenms_id"] == {"primary": 42}
+
+    def test_invalid_device_id_not_stored(self):
+        """Non-integer device_id is rejected and nothing is written."""
+        from netbox_librenms_plugin.utils import set_librenms_device_id
+
+        obj = MagicMock()
+        obj.custom_field_data = {}
+        set_librenms_device_id(obj, "not-an-int", server_key="primary")
+        assert "librenms_id" not in obj.custom_field_data
+
+    def test_invalid_device_id_does_not_overwrite_existing(self):
+        """Existing valid value is preserved when new device_id is invalid."""
+        from netbox_librenms_plugin.utils import set_librenms_device_id
+
+        obj = MagicMock()
+        obj.custom_field_data = {"librenms_id": {"primary": 10}}
+        set_librenms_device_id(obj, None, server_key="primary")
+        assert obj.custom_field_data["librenms_id"] == {"primary": 10}
+
+    def test_legacy_bare_int_blocks_write(self):
+        """Legacy bare-integer value blocks the write (no silent migration)."""
+        from netbox_librenms_plugin.utils import set_librenms_device_id
+
+        obj = MagicMock()
+        obj.custom_field_data = {"librenms_id": 7}
+        set_librenms_device_id(obj, 99, server_key="secondary")
+        # Write must be skipped; user must use the migration workflow.
+        assert obj.custom_field_data["librenms_id"] == 7
+
+    def test_legacy_bare_string_int_blocks_write(self):
+        """Legacy bare numeric string value blocks the write (no silent migration)."""
+        from netbox_librenms_plugin.utils import set_librenms_device_id
+
+        obj = MagicMock()
+        obj.custom_field_data = {"librenms_id": "7"}
+        set_librenms_device_id(obj, 99, server_key="secondary")
+        # Write must be skipped; user must use the migration workflow.
+        assert obj.custom_field_data["librenms_id"] == "7"
+
+    def test_adds_new_server_key_to_existing_dict(self):
+        """Adding a new server key preserves existing keys."""
+        from netbox_librenms_plugin.utils import set_librenms_device_id
+
+        obj = MagicMock()
+        obj.custom_field_data = {"librenms_id": {"primary": 5}}
+        set_librenms_device_id(obj, 20, server_key="secondary")
+        assert obj.custom_field_data["librenms_id"] == {"primary": 5, "secondary": 20}
+
+    def test_string_integer_is_coerced(self):
+        """String '42' is coerced to int 42."""
+        from netbox_librenms_plugin.utils import set_librenms_device_id
+
+        obj = MagicMock()
+        obj.custom_field_data = {}
+        set_librenms_device_id(obj, "42", server_key="primary")
+        assert obj.custom_field_data["librenms_id"] == {"primary": 42}
+
+    def test_boolean_true_rejected(self):
+        """Boolean True is not accepted as a valid device_id (bool is subclass of int)."""
+        from netbox_librenms_plugin.utils import set_librenms_device_id
+
+        obj = MagicMock()
+        obj.custom_field_data = {}
+        set_librenms_device_id(obj, True, server_key="primary")
+        assert "librenms_id" not in obj.custom_field_data
+
+    def test_boolean_false_rejected(self):
+        """Boolean False is not accepted as a valid device_id."""
+        from netbox_librenms_plugin.utils import set_librenms_device_id
+
+        obj = MagicMock()
+        obj.custom_field_data = {"librenms_id": {"primary": 10}}
+        set_librenms_device_id(obj, False, server_key="primary")
+        # Existing mapping must be preserved
+        assert obj.custom_field_data["librenms_id"] == {"primary": 10}
+
+    def test_unexpected_cf_type_reset_to_empty(self):
+        """If custom_field_data has unexpected type for librenms_id, it is reset."""
+        from netbox_librenms_plugin.utils import set_librenms_device_id
+
+        obj = MagicMock()
+        obj.custom_field_data = {"librenms_id": "unexpected-string"}
+        set_librenms_device_id(obj, 5, server_key="primary")
+        assert obj.custom_field_data["librenms_id"] == {"primary": 5}
diff --git a/netbox_librenms_plugin/tests/test_mixins.py b/netbox_librenms_plugin/tests/test_mixins.py
index fb40e690ae..89a405675b 100644
--- a/netbox_librenms_plugin/tests/test_mixins.py
+++ b/netbox_librenms_plugin/tests/test_mixins.py
@@ -110,6 +110,22 @@ def test_get_cache_key_format(self):
         key = mixin.get_cache_key(obj, "ports")
         assert key == "librenms_ports_device_5"
 
+    def test_get_cache_key_includes_server_key(self):
+        """
+        Cache keys must be namespaced per server so two servers' data never collide.
+
+        Without server_key isolation a second server's stale ports list could be
+        returned to the wrong sync session.
+        """
+        mixin = self._make_mixin()
+        obj = MagicMock()
+        obj._meta.model_name = "device"
+        obj.pk = 5
+
+        key = mixin.get_cache_key(obj, "ports", server_key="srv1")
+        assert "srv1" in key
+        assert key == "librenms_ports_device_5_srv1"
+
     def test_get_cache_key_includes_model_name(self):
         mixin = self._make_mixin()
         obj = MagicMock()
@@ -120,6 +136,16 @@ def test_get_cache_key_includes_model_name(self):
         assert "virtualmachine" in key
         assert "10" in key
 
+    def test_get_cache_key_different_data_types(self):
+        mixin = self._make_mixin()
+        obj = MagicMock()
+        obj._meta.model_name = "device"
+        obj.pk = 1
+
+        key_ports = mixin.get_cache_key(obj, "ports", server_key="prod")
+        key_ips = mixin.get_cache_key(obj, "ips", server_key="prod")
+        assert key_ports != key_ips
+
     def test_get_last_fetched_key_format(self):
         mixin = self._make_mixin()
         obj = MagicMock()
@@ -129,6 +155,21 @@ def test_get_last_fetched_key_format(self):
         key = mixin.get_last_fetched_key(obj, "ports")
         assert key == "librenms_ports_last_fetched_device_3"  # exact string
 
+    def test_get_last_fetched_key_includes_server_key(self):
+        """
+        The last-fetched timestamp key must also be server-scoped.
+
+        If two servers share the same key the cache countdown would reflect the
+        wrong server's fetch time.
+        """
+        mixin = self._make_mixin()
+        obj = MagicMock()
+        obj._meta.model_name = "device"
+        obj.pk = 3
+
+        key = mixin.get_last_fetched_key(obj, "ports", server_key="srv1")
+        assert key == "librenms_ports_last_fetched_device_3_srv1"  # exact string
+
     def test_cache_key_different_pks_differ(self):
         mixin = self._make_mixin()
         obj1 = MagicMock()
@@ -152,3 +193,15 @@ def test_get_vlan_overrides_key_exists_and_differs_from_data_key(self):
         assert vlan_key == "librenms_vlan_group_overrides_device_7"
         data_key = mixin.get_cache_key(obj, "vlans")
         assert vlan_key != data_key
+
+    def test_get_vlan_overrides_key_server_scoped(self):
+        """VLAN overrides key includes server_key to avoid cross-server leakage."""
+        mixin = self._make_mixin()
+        obj = MagicMock()
+        obj._meta.model_name = "device"
+        obj.pk = 7
+
+        key_no_server = mixin.get_vlan_overrides_key(obj)
+        key_with_server = mixin.get_vlan_overrides_key(obj, server_key="prod")
+        assert key_with_server == "librenms_vlan_group_overrides_device_7_prod"
+        assert key_no_server != key_with_server
diff --git a/netbox_librenms_plugin/tests/test_permissions.py b/netbox_librenms_plugin/tests/test_permissions.py
index 50bc2b6d04..e443e6c6b8 100644
--- a/netbox_librenms_plugin/tests/test_permissions.py
+++ b/netbox_librenms_plugin/tests/test_permissions.py
@@ -656,7 +656,8 @@ def test_bulk_import_devices_checks_permissions(self, mock_api_class, mock_requi
         call_args = mock_require.call_args
         assert user == call_args[0][0]
         assert "dcim.add_device" in call_args[0][1]
-        assert "dcim.add_interface" in call_args[0][1]
+        assert "dcim.change_device" in call_args[0][1]
+        assert "dcim.add_interface" not in call_args[0][1]
 
     @patch("netbox_librenms_plugin.import_utils.bulk_import.require_permissions")
     @patch("netbox_librenms_plugin.import_utils.bulk_import.LibreNMSAPI")
@@ -892,7 +893,9 @@ def test_bulk_import_devices_checks_vc_permission(self, mock_api_class, mock_req
 
         mock_require.assert_called_once()
         call_args = mock_require.call_args
-        assert "dcim.add_virtualchassis" in call_args[0][1]
+        # After Fix 6: interface/VC permissions removed from initial check
+        assert "dcim.add_virtualchassis" not in call_args[0][1]
+        assert "dcim.add_device" in call_args[0][1]
 
 
 class TestObjectTypeValidation:
@@ -951,3 +954,130 @@ def test_delete_interfaces_invalid_type_raises_404(self):
         view = DeleteNetBoxInterfacesView()
         with pytest.raises(Http404):
             view.get_required_permissions_for_object_type("invalid")
+
+
+# ---------------------------------------------------------------------------
+# Tests for RemoveServerMappingView error handling (device_fields.py)
+# ---------------------------------------------------------------------------
+
+
+class TestRemoveServerMappingViewErrorHandling:
+    """Test RemoveServerMappingView handles full_clean/save failures gracefully."""
+
+    def _make_view(self, server_key, post_extra=None):
+        """Return a (view, request) pair with permissions satisfied."""
+        from unittest.mock import MagicMock
+
+        from netbox_librenms_plugin.views.sync.device_fields import RemoveServerMappingView
+
+        request = MagicMock()
+        request.POST = {"server_key": server_key, **(post_extra or {})}
+        request.user = MagicMock()
+        request.user.has_perm.return_value = True
+
+        view = RemoveServerMappingView()
+        view.request = request  # required by mixin's has_write_permission
+        return view, request
+
+    def test_validation_error_returns_error_message(self):
+        """ValidationError from full_clean leads to error message, not 500."""
+        from unittest.mock import MagicMock, patch
+
+        from django.core.exceptions import ValidationError
+
+        view, request = self._make_view(server_key="orphan-server")
+
+        mock_device = MagicMock()
+        mock_device.custom_field_data = {"librenms_id": {"orphan-server": 99}}
+
+        mock_locked = MagicMock()
+        mock_locked.custom_field_data = {"librenms_id": {"orphan-server": 99}}
+        mock_locked.full_clean.side_effect = ValidationError("CF validation failed")
+
+        plugins_cfg = {"netbox_librenms_plugin": {"servers": {}}}  # orphan-server NOT configured
+
+        with (
+            patch("netbox_librenms_plugin.views.sync.device_fields.get_object_or_404", return_value=mock_device),
+            patch("netbox_librenms_plugin.views.sync.device_fields.Device") as mock_Device_cls,
+            patch("django.conf.settings") as mock_settings,
+            patch("netbox_librenms_plugin.views.sync.device_fields.messages") as mock_messages,
+            patch("netbox_librenms_plugin.views.sync.device_fields.redirect"),
+            patch("netbox_librenms_plugin.views.sync.device_fields.transaction") as mock_tx,
+        ):
+            mock_settings.PLUGINS_CONFIG = plugins_cfg
+            mock_Device_cls.objects.select_for_update.return_value.get.return_value = mock_locked
+
+            # Make transaction.atomic() a no-op context manager
+            mock_tx.atomic.return_value.__enter__ = lambda s: None
+            mock_tx.atomic.return_value.__exit__ = lambda s, *a: None
+            mock_tx.set_rollback = MagicMock()
+
+            view.post(request, pk=1)
+
+        mock_messages.error.assert_called_once()
+        error_args = mock_messages.error.call_args[0]
+        assert "Validation error" in str(error_args[1]) or "CF validation failed" in str(error_args[1])
+
+    def test_configured_server_refused(self):
+        """Configured server mapping cannot be removed — error message shown."""
+        from unittest.mock import MagicMock, patch
+
+        view, request = self._make_view(server_key="active-server")
+        mock_device = MagicMock()
+        mock_device.custom_field_data = {"librenms_id": {"active-server": 5}}
+
+        plugins_cfg = {"netbox_librenms_plugin": {"servers": {"active-server": {"librenms_url": "http://x"}}}}
+
+        with (
+            patch("netbox_librenms_plugin.views.sync.device_fields.get_object_or_404", return_value=mock_device),
+            patch("django.conf.settings") as mock_settings,
+            patch("netbox_librenms_plugin.views.sync.device_fields.messages") as mock_messages,
+            patch("netbox_librenms_plugin.views.sync.device_fields.redirect"),
+        ):
+            mock_settings.PLUGINS_CONFIG = plugins_cfg
+            view.post(request, pk=1)
+
+        mock_messages.error.assert_called_once()
+        assert "Cannot remove" in mock_messages.error.call_args[0][1]
+
+    def test_successful_removal_mutates_and_saves(self):
+        """Successful removal deletes the key from custom_field_data and saves the device."""
+        from unittest.mock import MagicMock, patch
+
+        view, request = self._make_view(server_key="orphan-server")
+
+        mock_device = MagicMock()
+        mock_device.custom_field_data = {"librenms_id": {"orphan-server": 42, "other-server": 7}}
+
+        mock_locked = MagicMock()
+        mock_locked.custom_field_data = {"librenms_id": {"orphan-server": 42, "other-server": 7}}
+        mock_locked.full_clean = MagicMock()
+        mock_locked.save = MagicMock()
+
+        plugins_cfg = {"netbox_librenms_plugin": {"servers": {}}}  # orphan-server NOT configured
+
+        with (
+            patch("netbox_librenms_plugin.views.sync.device_fields.get_object_or_404", return_value=mock_device),
+            patch("netbox_librenms_plugin.views.sync.device_fields.Device") as mock_Device_cls,
+            patch("django.conf.settings") as mock_settings,
+            patch("netbox_librenms_plugin.views.sync.device_fields.messages") as mock_messages,
+            patch("netbox_librenms_plugin.views.sync.device_fields.redirect"),
+            patch("netbox_librenms_plugin.views.sync.device_fields.transaction") as mock_tx,
+        ):
+            mock_settings.PLUGINS_CONFIG = plugins_cfg
+            mock_Device_cls.objects.select_for_update.return_value.get.return_value = mock_locked
+
+            mock_tx.atomic.return_value.__enter__ = lambda s: None
+            mock_tx.atomic.return_value.__exit__ = lambda s, *a: None
+            mock_tx.set_rollback = MagicMock()
+
+            view.post(request, pk=1)
+
+        # The "orphan-server" key should have been removed and the device saved.
+        # Assert the exact shape of custom_field_data so misspelled keys are caught.
+        assert mock_locked.custom_field_data == {"librenms_id": {"other-server": 7}}
+        remaining = mock_locked.custom_field_data["librenms_id"]
+        assert "orphan-server" not in remaining
+        assert remaining.get("other-server") == 7  # sibling key preserved
+        mock_locked.save.assert_called_once()
+        mock_messages.success.assert_called_once()
diff --git a/netbox_librenms_plugin/tests/test_sync_devices.py b/netbox_librenms_plugin/tests/test_sync_devices.py
index 49b1f318c8..a8df67693a 100644
--- a/netbox_librenms_plugin/tests/test_sync_devices.py
+++ b/netbox_librenms_plugin/tests/test_sync_devices.py
@@ -254,3 +254,110 @@ def test_validation_error_caught_on_slug_collision(self):
             error_msg = mock_messages.error.call_args[0][1]
             assert "could not be created" in error_msg
             assert "Slug already exists" in error_msg
+
+
+class TestRemoveServerMappingViewWiring:
+    def test_does_not_have_librenms_api_mixin(self):
+        """RemoveServerMappingView does not call LibreNMS API — it only modifies NetBox."""
+        from netbox_librenms_plugin.views.sync.device_fields import RemoveServerMappingView
+        from netbox_librenms_plugin.views.mixins import LibreNMSAPIMixin
+
+        assert LibreNMSAPIMixin not in RemoveServerMappingView.__mro__
+
+    def test_has_permission_mixin(self):
+        from netbox_librenms_plugin.views.sync.device_fields import RemoveServerMappingView
+        from netbox_librenms_plugin.views.mixins import LibreNMSPermissionMixin, NetBoxObjectPermissionMixin
+
+        assert LibreNMSPermissionMixin in RemoveServerMappingView.__mro__
+        assert NetBoxObjectPermissionMixin in RemoveServerMappingView.__mro__
+
+    def test_post_with_virtualmachine_sets_vm_permissions_and_redirects(self):
+        """post() with object_type='virtualmachine' sets VirtualMachine permissions and redirects to VM URL."""
+        from netbox_librenms_plugin.views.sync.device_fields import RemoveServerMappingView
+        from virtualization.models import VirtualMachine
+
+        view = object.__new__(RemoveServerMappingView)
+
+        permissions_at_check = {}
+
+        def capture_perms(method):
+            permissions_at_check[method] = list(view.required_object_permissions.get(method, []))
+            return None  # permission passes
+
+        mock_vm = MagicMock()
+        mock_vm.pk = 10
+        mock_vm.custom_field_data = {"librenms_id": {"orphaned-server": 42}}
+
+        # Use a mock model class so the select_for_update().get() call doesn't hit the DB
+        mock_model = MagicMock()
+        mock_model.objects.select_for_update.return_value.get.return_value = mock_vm
+
+        request = MagicMock()
+        request.POST = {"object_type": "virtualmachine", "server_key": "orphaned-server"}
+
+        with (
+            patch.object(view, "require_all_permissions", side_effect=capture_perms),
+            patch.object(view, "_get_object", return_value=(mock_vm, mock_model)),
+            patch("netbox_librenms_plugin.views.sync.device_fields.messages"),
+            patch("netbox_librenms_plugin.views.sync.device_fields.redirect") as mock_redirect,
+            patch("netbox_librenms_plugin.views.sync.device_fields.transaction"),
+            patch(
+                "django.conf.settings",
+                PLUGINS_CONFIG={"netbox_librenms_plugin": {}},
+            ),
+        ):
+            view.post(request, pk=10)
+
+        # required_object_permissions must be scoped to VirtualMachine, not Device
+        assert ("change", VirtualMachine) in permissions_at_check.get("POST", [])
+        # Response must redirect to the VM-specific sync URL
+        mock_redirect.assert_called_with("plugins:netbox_librenms_plugin:vm_librenms_sync", pk=10)
+
+
+class TestNormalizeLibreNMSMapping:
+    """_normalize_librenms_mapping must reject booleans and non-digit strings."""
+
+    def _call(self, value):
+        # Instantiate the view class minimally to access the method
+        from netbox_librenms_plugin.views.sync.device_fields import RemoveServerMappingView
+
+        view = object.__new__(RemoveServerMappingView)
+        return view._normalize_librenms_mapping(value)
+
+    def test_int_becomes_default_dict(self):
+        assert self._call(42) == {"default": 42}
+
+    def test_bool_true_returns_empty(self):
+        assert self._call(True) == {}
+
+    def test_bool_false_returns_empty(self):
+        assert self._call(False) == {}
+
+    def test_digit_string_coerced(self):
+        assert self._call("42") == {"default": 42}
+
+    def test_non_digit_string_returns_empty(self):
+        assert self._call("not-a-number") == {}
+
+    def test_plus_prefix_rejected(self):
+        """'+1' is not strictly digit-only."""
+        assert self._call("+1") == {}
+
+    def test_space_padded_rejected(self):
+        """' 42 ' is not strictly digit-only."""
+        assert self._call(" 42 ") == {}
+
+    def test_dict_passed_through(self):
+        d = {"production": 7}
+        assert self._call(d) is d
+
+    def test_none_returns_empty(self):
+        assert self._call(None) == {}
+
+    def test_list_returns_empty(self):
+        assert self._call([1, 2]) == {}
+
+
+# ---------------------------------------------------------------------------
+# all_server_mappings — did validation
+# ---------------------------------------------------------------------------
diff --git a/netbox_librenms_plugin/tests/test_sync_view_mismatch.py b/netbox_librenms_plugin/tests/test_sync_view_mismatch.py
index 6aead1cfa8..3aaf4213b6 100644
--- a/netbox_librenms_plugin/tests/test_sync_view_mismatch.py
+++ b/netbox_librenms_plugin/tests/test_sync_view_mismatch.py
@@ -345,7 +345,7 @@ def test_vc_member_with_own_id_delegates_to_sync_device(self, mock_sync_device,
         # Viewed device: member A with its own librenms_id
         member_a = MagicMock()
         member_a.pk = 1
-        member_a.cf = {"librenms_id": 42}
+        member_a.cf = {"librenms_id": {"default": 42}}
         member_a.virtual_chassis = MagicMock()
 
         # Sync device: member B (returned by get_librenms_sync_device)
@@ -358,6 +358,7 @@ def test_vc_member_with_own_id_delegates_to_sync_device(self, mock_sync_device,
         view = object.__new__(BaseLibreNMSSyncView)
         view.model = MagicMock()
         api = MagicMock()
+        api.server_key = "default"
         api.get_librenms_id.return_value = 42
         view._librenms_api = api
         view.tab = MagicMock()
@@ -368,7 +369,7 @@ def test_vc_member_with_own_id_delegates_to_sync_device(self, mock_sync_device,
         view.get(request, pk=1)
 
         # get_librenms_sync_device must be called unconditionally for VC members
-        mock_sync_device.assert_called_once_with(member_a)
+        mock_sync_device.assert_called_once_with(member_a, server_key="default")
         # get_librenms_id should be called on the sync device (member_b)
         api.get_librenms_id.assert_called_once_with(member_b)
 
@@ -390,6 +391,7 @@ def test_non_vc_device_skips_sync_device_lookup(self, mock_sync_device, mock_get
         view = object.__new__(BaseLibreNMSSyncView)
         view.model = MagicMock()
         api = MagicMock()
+        api.server_key = "default"
         api.get_librenms_id.return_value = 42
         view._librenms_api = api
         view.tab = MagicMock()
@@ -400,3 +402,256 @@ def test_non_vc_device_skips_sync_device_lookup(self, mock_sync_device, mock_get
         view.get(request, pk=1)
 
         mock_sync_device.assert_not_called()
+        assert view._librenms_lookup_device == device
+
+    @patch("netbox_librenms_plugin.views.base.librenms_sync_view.render")
+    @patch("netbox_librenms_plugin.views.base.librenms_sync_view.get_object_or_404")
+    @patch("netbox_librenms_plugin.views.base.librenms_sync_view.get_librenms_sync_device")
+    def test_vc_member_with_legacy_id_delegates_to_sync_device(self, mock_sync_device, mock_get_object, mock_render):
+        """
+        A VC member with a legacy bare-int librenms_id should still
+        delegate to get_librenms_sync_device, which may return a different
+        member with a per-server dict format."""
+        from netbox_librenms_plugin.views.base.librenms_sync_view import BaseLibreNMSSyncView
+
+        # Viewed device: member A with legacy bare-int
+        member_a = MagicMock()
+        member_a.pk = 1
+        member_a.cf = {"librenms_id": 42}
+        member_a.virtual_chassis = MagicMock()
+
+        # Sync device: member B (per-server dict, returned by get_librenms_sync_device)
+        member_b = MagicMock()
+        member_b.pk = 2
+        member_b.cf = {"librenms_id": {"default": 42}}
+
+        mock_get_object.return_value = member_a
+        mock_sync_device.return_value = member_b
+
+        view = object.__new__(BaseLibreNMSSyncView)
+        view.model = MagicMock()
+        api = MagicMock()
+        api.server_key = "default"
+        api.get_librenms_id.return_value = 42
+        view._librenms_api = api
+        view.tab = MagicMock()
+        view.get_context_data = MagicMock(return_value={})
+        mock_render.return_value = MagicMock()
+
+        request = MagicMock()
+        view.get(request, pk=1)
+
+        # get_librenms_sync_device must be called unconditionally for VC members
+        mock_sync_device.assert_called_once_with(member_a, server_key="default")
+        # The lookup device should be member_b, not member_a
+        assert view._librenms_lookup_device == member_b
+        # get_librenms_id should be called on the sync device (member_b)
+        api.get_librenms_id.assert_called_once_with(member_b)
+
+    @patch("netbox_librenms_plugin.views.base.librenms_sync_view.render")
+    @patch("netbox_librenms_plugin.views.base.librenms_sync_view.get_object_or_404")
+    @patch("netbox_librenms_plugin.views.base.librenms_sync_view.get_librenms_sync_device")
+    def test_vc_member_with_legacy_id_delegates_to_sync_device_returns_member_b(
+        self, mock_sync_device, mock_get_object, mock_render
+    ):
+        """
+        A VC member with a legacy bare-int librenms_id still delegates to
+        get_librenms_sync_device so an explicit per-server mapping on another
+        member takes priority."""
+        from netbox_librenms_plugin.views.base.librenms_sync_view import BaseLibreNMSSyncView
+
+        # Viewed device: member A with legacy bare-int
+        member_a = MagicMock()
+        member_a.pk = 1
+        member_a.cf = {"librenms_id": 42}
+        member_a.virtual_chassis = MagicMock()
+
+        # Sync device: member B (per-server dict preferred by helper)
+        member_b = MagicMock()
+        member_b.pk = 2
+        member_b.cf = {"librenms_id": {"default": 42}}
+
+        mock_get_object.return_value = member_a
+        mock_sync_device.return_value = member_b
+
+        view = object.__new__(BaseLibreNMSSyncView)
+        view.model = MagicMock()
+        api = MagicMock()
+        api.server_key = "default"
+        api.get_librenms_id.return_value = 42
+        view._librenms_api = api
+        view.tab = MagicMock()
+        view.get_context_data = MagicMock(return_value={})
+        mock_render.return_value = MagicMock()
+
+        request = MagicMock()
+        view.get(request, pk=1)
+
+        # Must always delegate — even with a legacy bare-int on the viewed member
+        mock_sync_device.assert_called_once_with(member_a, server_key="default")
+        # Lookup device is member_b (per-server mapping wins)
+        assert view._librenms_lookup_device is member_b
+        api.get_librenms_id.assert_called_once_with(member_b)
+
+    @patch("netbox_librenms_plugin.views.base.librenms_sync_view.render")
+    @patch("netbox_librenms_plugin.views.base.librenms_sync_view.get_object_or_404")
+    @patch("netbox_librenms_plugin.views.base.librenms_sync_view.get_librenms_sync_device")
+    def test_vc_member_with_own_active_id_stays_as_lookup_device(self, mock_sync_device, mock_get_object, mock_render):
+        """
+        A VC member that has its own per-server librenms_id for the active server
+        stays as _librenms_lookup_device when get_librenms_sync_device returns it."""
+        from netbox_librenms_plugin.views.base.librenms_sync_view import BaseLibreNMSSyncView
+
+        # Viewed device: member A with its own per-server mapping for the active server
+        member_a = MagicMock()
+        member_a.pk = 1
+        member_a.cf = {"librenms_id": {"default": 42}}
+        member_a.virtual_chassis = MagicMock()
+
+        # get_librenms_sync_device returns member_a itself (it owns the active mapping)
+        mock_get_object.return_value = member_a
+        mock_sync_device.return_value = member_a
+
+        view = object.__new__(BaseLibreNMSSyncView)
+        view.model = MagicMock()
+        api = MagicMock()
+        api.server_key = "default"
+        api.get_librenms_id.return_value = 42
+        view._librenms_api = api
+        view.tab = MagicMock()
+        view.get_context_data = MagicMock(return_value={})
+        mock_render.return_value = MagicMock()
+
+        request = MagicMock()
+        view.get(request, pk=1)
+
+        mock_sync_device.assert_called_once_with(member_a, server_key="default")
+        # Member stays as lookup device because get_librenms_sync_device returned it
+        assert view._librenms_lookup_device is member_a
+        api.get_librenms_id.assert_called_once_with(member_a)
+
+    @patch("netbox_librenms_plugin.views.base.librenms_sync_view.render")
+    @patch("netbox_librenms_plugin.views.base.librenms_sync_view.get_object_or_404")
+    @patch("netbox_librenms_plugin.views.base.librenms_sync_view.get_librenms_sync_device")
+    def test_vc_member_without_active_id_delegates_to_primary(self, mock_sync_device, mock_get_object, mock_render):
+        """
+        A VC member with NO per-server librenms_id for the active server delegates
+        to the VC primary returned by get_librenms_sync_device."""
+        from netbox_librenms_plugin.views.base.librenms_sync_view import BaseLibreNMSSyncView
+
+        # Viewed device: member with no active-server mapping
+        member = MagicMock()
+        member.pk = 1
+        member.cf = {"librenms_id": {}}
+        member.virtual_chassis = MagicMock()
+
+        # VC primary has the active mapping
+        vc_primary = MagicMock()
+        vc_primary.pk = 99
+        vc_primary.cf = {"librenms_id": {"default": 7}}
+
+        mock_get_object.return_value = member
+        mock_sync_device.return_value = vc_primary
+
+        view = object.__new__(BaseLibreNMSSyncView)
+        view.model = MagicMock()
+        api = MagicMock()
+        api.server_key = "default"
+        api.get_librenms_id.return_value = 7
+        view._librenms_api = api
+        view.tab = MagicMock()
+        view.get_context_data = MagicMock(return_value={})
+        mock_render.return_value = MagicMock()
+
+        request = MagicMock()
+        view.get(request, pk=1)
+
+        mock_sync_device.assert_called_once_with(member, server_key="default")
+        # Lookup device delegates to VC primary
+        assert view._librenms_lookup_device is vc_primary
+        api.get_librenms_id.assert_called_once_with(vc_primary)
+
+
+# ---------------------------------------------------------------------------
+# Tests for _build_all_server_mappings
+# ---------------------------------------------------------------------------
+
+
+class TestBuildAllServerMappings:
+    """Tests for BaseLibreNMSSyncView._build_all_server_mappings."""
+
+    def test_returns_none_for_legacy_int(self, mock_netbox_device):
+        from netbox_librenms_plugin.views.base.librenms_sync_view import BaseLibreNMSSyncView
+
+        mock_netbox_device.custom_field_data = {"librenms_id": 42}
+        result = BaseLibreNMSSyncView._build_all_server_mappings(mock_netbox_device, "production")
+        assert result is None
+
+    def test_returns_none_for_missing_cf(self, mock_netbox_device):
+        from netbox_librenms_plugin.views.base.librenms_sync_view import BaseLibreNMSSyncView
+
+        mock_netbox_device.custom_field_data = {"librenms_id": None}
+        result = BaseLibreNMSSyncView._build_all_server_mappings(mock_netbox_device, "production")
+        assert result is None
+
+    def test_single_configured_server(self, mock_netbox_device, mock_plugins_config_single_server):
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.views.base.librenms_sync_view import BaseLibreNMSSyncView
+
+        mock_netbox_device.custom_field_data = {"librenms_id": {"production": 42}}
+        with patch("netbox_librenms_plugin.views.base.librenms_sync_view.django_settings") as mock_settings:
+            mock_settings.PLUGINS_CONFIG = mock_plugins_config_single_server
+            result = BaseLibreNMSSyncView._build_all_server_mappings(mock_netbox_device, "production")
+
+        assert result is not None
+        assert len(result) == 1
+        entry = result[0]
+        assert entry["server_key"] == "production"
+        assert entry["device_id"] == 42
+        assert entry["display_name"] == "Production LibreNMS"
+        assert entry["is_configured"] is True
+        assert entry["is_active"] is True
+        assert entry["device_url"] == "https://librenms.example.com/device/device=42/"
+
+    def test_orphaned_server_is_not_configured(self, mock_netbox_device, mock_plugins_config_empty_servers):
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.views.base.librenms_sync_view import BaseLibreNMSSyncView
+
+        mock_netbox_device.custom_field_data = {"librenms_id": {"deleted-server": 77}}
+        with patch("netbox_librenms_plugin.views.base.librenms_sync_view.django_settings") as mock_settings:
+            mock_settings.PLUGINS_CONFIG = mock_plugins_config_empty_servers
+            result = BaseLibreNMSSyncView._build_all_server_mappings(mock_netbox_device, "production")
+
+        assert result is not None
+        assert len(result) == 1
+        entry = result[0]
+        assert entry["server_key"] == "deleted-server"
+        assert entry["device_id"] == 77
+        assert entry["is_configured"] is False
+        assert entry["is_active"] is False
+        assert entry["device_url"] is None
+
+    def test_multiple_servers_sorted_active_first(self, mock_netbox_device, mock_plugins_config_multi_server_mapping):
+        from unittest.mock import patch
+
+        from netbox_librenms_plugin.views.base.librenms_sync_view import BaseLibreNMSSyncView
+
+        mock_netbox_device.custom_field_data = {"librenms_id": {"mock-dev": 99, "production": 42, "old-server": 11}}
+        with patch("netbox_librenms_plugin.views.base.librenms_sync_view.django_settings") as mock_settings:
+            mock_settings.PLUGINS_CONFIG = mock_plugins_config_multi_server_mapping
+            result = BaseLibreNMSSyncView._build_all_server_mappings(mock_netbox_device, "production")
+
+        assert result is not None
+        assert len(result) == 3
+        # Active (production) first
+        assert result[0]["server_key"] == "production"
+        assert result[0]["is_active"] is True
+        # Configured (mock-dev) second
+        assert result[1]["server_key"] == "mock-dev"
+        assert result[1]["is_configured"] is True
+        assert result[1]["is_active"] is False
+        # Orphaned last
+        assert result[2]["server_key"] == "old-server"
+        assert result[2]["is_configured"] is False
diff --git a/netbox_librenms_plugin/tests/test_utils.py b/netbox_librenms_plugin/tests/test_utils.py
index 09310a1198..e78144e149 100644
--- a/netbox_librenms_plugin/tests/test_utils.py
+++ b/netbox_librenms_plugin/tests/test_utils.py
@@ -16,9 +16,12 @@
 class TestDeviceTypeMatching:
     """Test device type matching logic."""
 
+    @patch("netbox_librenms_plugin.models.DeviceTypeMapping", create=True)
     @patch("dcim.models.DeviceType")
-    def test_match_device_type_exact_match_by_part_number(self, mock_device_type):
+    def test_match_device_type_exact_match_by_part_number(self, mock_device_type, mock_dtm):
         """Exact part_number string should match."""
+        mock_dtm.DoesNotExist = Exception
+        mock_dtm.objects.get.side_effect = Exception
         mock_dt = MagicMock(id=1, model="C9300-48P")
         mock_device_type.objects.get.return_value = mock_dt
 
@@ -30,9 +33,12 @@ def test_match_device_type_exact_match_by_part_number(self, mock_device_type):
         assert result["device_type"] == mock_dt
         assert result["match_type"] == "exact"
 
+    @patch("netbox_librenms_plugin.models.DeviceTypeMapping", create=True)
     @patch("dcim.models.DeviceType")
-    def test_match_device_type_exact_match_by_model(self, mock_device_type):
+    def test_match_device_type_exact_match_by_model(self, mock_device_type, mock_dtm):
         """Exact model string should match when part_number fails."""
+        mock_dtm.DoesNotExist = Exception
+        mock_dtm.objects.get.side_effect = Exception
         mock_dt = MagicMock(id=1, model="WS-C3750X-48P")
         # Part number lookup fails, model lookup succeeds
         mock_device_type.DoesNotExist = Exception
@@ -49,9 +55,12 @@ def test_match_device_type_exact_match_by_model(self, mock_device_type):
         assert result["device_type"] == mock_dt
         assert result["match_type"] == "exact"
 
+    @patch("netbox_librenms_plugin.models.DeviceTypeMapping", create=True)
     @patch("dcim.models.DeviceType")
-    def test_match_device_type_not_found(self, mock_device_type):
-        """Returns None when no match found."""
+    def test_match_device_type_not_found(self, mock_device_type, mock_dtm):
+        """Returns not-found dict when no match found."""
+        mock_dtm.DoesNotExist = Exception
+        mock_dtm.objects.get.side_effect = Exception
         mock_device_type.DoesNotExist = Exception
         mock_device_type.objects.get.side_effect = mock_device_type.DoesNotExist
 
@@ -347,74 +356,202 @@ def test_get_librenms_sync_device_with_librenms_id(self):
 
         assert result == mock_member_with_id
 
-    def test_get_librenms_sync_device_member_with_id_preferred(self):
-        """A VC member with librenms_id set is preferred over members without."""
+    def test_get_librenms_sync_device_dict_preferred_over_legacy_bare_int(self):
+        """
+        In a partially migrated VC, a member with per-server dict format
+        is preferred over a member with legacy bare-int format."""
         from netbox_librenms_plugin.utils import get_librenms_sync_device
 
+        # Member A: legacy bare-int librenms_id (not yet migrated)
         member_a = MagicMock()
-        member_a.cf = {}
+        member_a.cf = {"librenms_id": 42}
 
+        # Member B: migrated per-server dict format
         member_b = MagicMock()
-        member_b.cf = {"librenms_id": 42}
+        member_b.cf = {"librenms_id": {"default": 42}}
 
         mock_device = MagicMock()
         mock_device.virtual_chassis = MagicMock()
+        # member_a listed first — the function should still prefer member_b
         mock_device.virtual_chassis.members.all.return_value = [member_a, member_b]
 
-        result = get_librenms_sync_device(mock_device)
+        result = get_librenms_sync_device(mock_device, server_key="default")
 
         assert result == member_b
 
-    def test_get_librenms_sync_device_fallback_to_master_with_ip(self):
-        """When no member has librenms_id, fall back to master with primary IP."""
+    def test_get_librenms_sync_device_legacy_fallback_when_no_dict(self):
+        """When no member has a per-server dict, fall back to legacy bare-int."""
         from netbox_librenms_plugin.utils import get_librenms_sync_device
 
         member_a = MagicMock()
-        member_a.cf = {}
-        member_a.primary_ip = MagicMock()
-
+        member_a.cf = {"librenms_id": 42}
         member_b = MagicMock()
         member_b.cf = {}
-        member_b.primary_ip = None
 
         mock_device = MagicMock()
         mock_device.virtual_chassis = MagicMock()
-        mock_device.virtual_chassis.master = member_a
-        mock_device.virtual_chassis.master.primary_ip = MagicMock()
-        mock_device.virtual_chassis.members.all.return_value = [member_a, member_b]
+        mock_device.virtual_chassis.members.all.return_value = [member_b, member_a]
 
-        result = get_librenms_sync_device(mock_device)
+        result = get_librenms_sync_device(mock_device, server_key="default")
 
         assert result == member_a
 
-    def test_get_librenms_sync_device_fallback_to_any_member_with_ip(self):
-        """When no member has librenms_id and master has no IP, fall back to any member with IP."""
+    def test_get_librenms_sync_device_dict_for_different_server_falls_through(self):
+        """Per-server dict with a different key does not match; legacy bare-int resolves instead."""
         from netbox_librenms_plugin.utils import get_librenms_sync_device
 
+        # Member A: legacy bare-int (universal fallback)
         member_a = MagicMock()
-        member_a.cf = {}
-        member_a.primary_ip = None
+        member_a.cf = {"librenms_id": 42}
 
+        # Member B: dict but only for "production", not "default"
         member_b = MagicMock()
-        member_b.cf = {}
-        member_b.primary_ip = MagicMock()
+        member_b.cf = {"librenms_id": {"production": 99}}
 
         mock_device = MagicMock()
         mock_device.virtual_chassis = MagicMock()
-        mock_device.virtual_chassis.master = member_a
-        mock_device.virtual_chassis.master.primary_ip = None
         mock_device.virtual_chassis.members.all.return_value = [member_a, member_b]
 
-        result = get_librenms_sync_device(mock_device)
+        result = get_librenms_sync_device(mock_device, server_key="default")
 
-        assert result == member_b
+        assert result == member_a
+
+    def test_zero_id_is_still_valid(self):
+        """A zero-valued LibreNMS ID must not be treated as missing (is not None guard)."""
+        from netbox_librenms_plugin.utils import get_librenms_sync_device
+
+        device = MagicMock()
+        vc = MagicMock()
+        device.virtual_chassis = vc
+
+        member = MagicMock()
+        member.cf = {"librenms_id": 0}  # zero is a valid LibreNMS ID
+        member.custom_field_data = {"librenms_id": 0}
+
+        # Simulate get_librenms_device_id returning 0 (not None) for member
+        with patch("netbox_librenms_plugin.utils.get_librenms_device_id") as mock_get_id:
+            mock_get_id.side_effect = lambda obj, server_key, **kwargs: 0 if obj is member else None
+            vc.members.all.return_value = [member]
+            result = get_librenms_sync_device(device, server_key="default")
+
+        # 0 is a valid ID — should not be treated as "no ID"
+        assert result is member
 
 
 # =============================================================================
-# TestPaginationHelpers - 2 tests
+# TestSafeDisabled - tests for _safe_disabled in bulk_import.py and filters.py
 # =============================================================================
 
 
+class TestSafeDisabledBulkImport:
+    """Tests for _safe_disabled in import_utils/bulk_import.py."""
+
+    def _call(self, val):
+        from netbox_librenms_plugin.import_utils.bulk_import import _safe_disabled
+
+        return _safe_disabled({"disabled": val})
+
+    def test_bool_true(self):
+        assert self._call(True) == 1
+
+    def test_bool_false(self):
+        assert self._call(False) == 0
+
+    def test_string_true_lowercase(self):
+        assert self._call("true") == 1
+
+    def test_string_yes(self):
+        assert self._call("yes") == 1
+
+    def test_string_on(self):
+        assert self._call("on") == 1
+
+    def test_string_false_lowercase(self):
+        assert self._call("false") == 0
+
+    def test_string_no(self):
+        assert self._call("no") == 0
+
+    def test_string_off(self):
+        assert self._call("off") == 0
+
+    def test_numeric_one(self):
+        assert self._call(1) == 1
+
+    def test_numeric_zero(self):
+        assert self._call(0) == 0
+
+    def test_none_defaults_to_zero(self):
+        assert self._call(None) == 0
+
+    def test_missing_key_defaults_to_zero(self):
+        from netbox_librenms_plugin.import_utils.bulk_import import _safe_disabled
+
+        assert _safe_disabled({}) == 0
+
+    def test_string_true_uppercase(self):
+        assert self._call("TRUE") == 1
+
+    def test_non_zero_int_is_disabled(self):
+        assert self._call(2) == 1
+
+    def test_negative_int_is_disabled(self):
+        assert self._call(-1) == 1
+
+
+class TestSafeDisabledFilters:
+    """Tests for _safe_disabled in import_utils/filters.py (same contract)."""
+
+    def _call(self, val):
+        from netbox_librenms_plugin.import_utils.filters import _safe_disabled
+
+        return _safe_disabled({"disabled": val})
+
+    def test_bool_true(self):
+        assert self._call(True) == 1
+
+    def test_bool_false(self):
+        assert self._call(False) == 0
+
+    def test_string_true(self):
+        assert self._call("true") == 1
+
+    def test_string_yes(self):
+        assert self._call("yes") == 1
+
+    def test_string_on(self):
+        assert self._call("on") == 1
+
+    def test_string_false(self):
+        assert self._call("false") == 0
+
+    def test_string_off(self):
+        assert self._call("off") == 0
+
+    def test_string_uppercase_true(self):
+        assert self._call("TRUE") == 1
+
+    def test_string_no(self):
+        assert self._call("no") == 0
+
+    def test_numeric_one(self):
+        assert self._call(1) == 1
+
+    def test_none_defaults_to_zero(self):
+        assert self._call(None) == 0
+
+    def test_non_zero_int_is_disabled(self):
+        assert self._call(2) == 1
+
+    def test_negative_int_is_disabled(self):
+        assert self._call(-1) == 1
+
+    def test_missing_key_defaults_to_zero(self):
+        from netbox_librenms_plugin.import_utils.filters import _safe_disabled
+
+        assert _safe_disabled({}) == 0
+
+
 class TestPaginationHelpers:
     """Test pagination helper functions."""
 
diff --git a/netbox_librenms_plugin/tests/test_view_wiring.py b/netbox_librenms_plugin/tests/test_view_wiring.py
index 0576c06775..3c24202c32 100644
--- a/netbox_librenms_plugin/tests/test_view_wiring.py
+++ b/netbox_librenms_plugin/tests/test_view_wiring.py
@@ -7,6 +7,7 @@
 
 import os
 from pathlib import Path
+from unittest.mock import MagicMock, patch
 
 import pytest
 
@@ -64,6 +65,11 @@ def test_assign_vc_serial_has_librenms_api_mixin(self):
 
         self._assert_has_api_mixin(AssignVCSerialView)
 
+    def test_convert_legacy_id_has_librenms_api_mixin(self):
+        from netbox_librenms_plugin.views.sync.device_fields import ConvertLegacyLibreNMSIdView
+
+        self._assert_has_api_mixin(ConvertLegacyLibreNMSIdView)
+
 
 class TestCacheMixinWiring:
     """Views that cache LibreNMS data must have CacheMixin and expose get_cache_key."""
@@ -195,6 +201,18 @@ def test_update_device_serial_has_required_object_permissions(self):
         self._assert_has_mixins(UpdateDeviceSerialView)
         assert "POST" in UpdateDeviceSerialView.required_object_permissions
 
+    def test_remove_server_mapping_has_required_object_permissions(self):
+        from netbox_librenms_plugin.views.sync.device_fields import RemoveServerMappingView
+
+        self._assert_has_mixins(RemoveServerMappingView)
+        assert "POST" in RemoveServerMappingView.required_object_permissions
+
+    def test_convert_legacy_id_has_required_object_permissions(self):
+        from netbox_librenms_plugin.views.sync.device_fields import ConvertLegacyLibreNMSIdView
+
+        self._assert_has_mixins(ConvertLegacyLibreNMSIdView)
+        assert "POST" in ConvertLegacyLibreNMSIdView.required_object_permissions
+
     def test_delete_interfaces_has_required_object_permissions(self):
         from dcim.models import Interface
         from virtualization.models import VMInterface
@@ -234,16 +252,10 @@ class DummyView(LibreNMSAPIMixin):
         assert dummy._librenms_api is None
 
     def test_sync_interfaces_has_librenms_api_property_via_class(self):
-        """
-        BaseLibreNMSSyncView must expose librenms_api through its MRO.
-
-        SyncInterfacesView gains LibreNMSAPIMixin in the view-fixes PR; on the
-        current upstream/develop baseline we verify the property via
-        BaseLibreNMSSyncView, which inherits the mixin unconditionally.
-        """
-        from netbox_librenms_plugin.views.base.librenms_sync_view import BaseLibreNMSSyncView
+        """SyncInterfacesView must expose librenms_api through its MRO."""
+        from netbox_librenms_plugin.views.sync.interfaces import SyncInterfacesView
 
-        assert any("librenms_api" in vars(cls) for cls in BaseLibreNMSSyncView.__mro__)
+        assert any("librenms_api" in vars(cls) for cls in SyncInterfacesView.__mro__)
 
 
 # ── Template syntax smoke tests ──────────────────────────────────────────────
@@ -306,3 +318,147 @@ def test_member_name_is_escaped(self):
 
         assert "<script>" not in html
         assert "&lt;script&gt;" in html
+
+
+class TestAllServerMappingsDidValidation:
+    """all_server_mappings must skip invalid device IDs in the cf_value dict."""
+
+    def _call(self, obj, active_server_key="default"):
+        from netbox_librenms_plugin.views.base.librenms_sync_view import BaseLibreNMSSyncView
+
+        return BaseLibreNMSSyncView._build_all_server_mappings(obj, active_server_key)
+
+    @patch("netbox_librenms_plugin.views.base.librenms_sync_view.django_settings")
+    def test_skips_boolean_did(self, mock_settings):
+        mock_settings.PLUGINS_CONFIG = {"netbox_librenms_plugin": {"servers": {}}}
+        obj = MagicMock()
+        obj.custom_field_data = {"librenms_id": {"default": True, "prod": 42}}
+        result = self._call(obj)
+        # Only prod=42 should survive
+        assert len(result) == 1
+        assert result[0]["device_id"] == 42
+
+    @patch("netbox_librenms_plugin.views.base.librenms_sync_view.django_settings")
+    def test_skips_none_did(self, mock_settings):
+        mock_settings.PLUGINS_CONFIG = {"netbox_librenms_plugin": {"servers": {}}}
+        obj = MagicMock()
+        obj.custom_field_data = {"librenms_id": {"default": None}}
+        result = self._call(obj)
+        assert result is None  # empty list → returns None
+
+    @patch("netbox_librenms_plugin.views.base.librenms_sync_view.django_settings")
+    def test_coerces_digit_string_did(self, mock_settings):
+        mock_settings.PLUGINS_CONFIG = {"netbox_librenms_plugin": {"servers": {}}}
+        obj = MagicMock()
+        obj.custom_field_data = {"librenms_id": {"prod": "99"}}
+        result = self._call(obj)
+        assert len(result) == 1
+        assert result[0]["device_id"] == 99
+
+    @patch("netbox_librenms_plugin.views.base.librenms_sync_view.django_settings")
+    def test_skips_non_digit_string_did(self, mock_settings):
+        mock_settings.PLUGINS_CONFIG = {"netbox_librenms_plugin": {"servers": {}}}
+        obj = MagicMock()
+        obj.custom_field_data = {"librenms_id": {"default": "bogus"}}
+        result = self._call(obj)
+        assert result is None
+
+    @patch("netbox_librenms_plugin.views.base.librenms_sync_view.django_settings")
+    def test_valid_int_passes_through(self, mock_settings):
+        mock_settings.PLUGINS_CONFIG = {"netbox_librenms_plugin": {"servers": {}}}
+        obj = MagicMock()
+        obj.custom_field_data = {"librenms_id": {"default": 5, "secondary": 10}}
+        result = self._call(obj)
+        assert len(result) == 2
+        ids = {e["device_id"] for e in result}
+        assert ids == {5, 10}
+
+
+# ---------------------------------------------------------------------------
+# render_device_selection — XSS escape
+# ---------------------------------------------------------------------------
+
+
+class TestSingleCableVerifyServerKey:
+    """SingleCableVerifyView.post() must read server_key from POST body."""
+
+    def test_server_key_used_for_cache_lookup(self):
+        """The server_key from POST body is passed to get_cache_key and get_librenms_sync_device."""
+        import json
+
+        from netbox_librenms_plugin.views.base.cables_view import SingleCableVerifyView
+
+        view = object.__new__(SingleCableVerifyView)
+        view._librenms_api = MagicMock()
+        view._librenms_api.server_key = "default-server"
+
+        request = MagicMock()
+        request.body = json.dumps(
+            {
+                "device_id": 1,
+                "local_port_id": "42",
+                "server_key": "production",
+            }
+        ).encode()
+
+        with (
+            patch("netbox_librenms_plugin.views.base.cables_view.get_object_or_404") as mock_get_obj,
+            patch(
+                "netbox_librenms_plugin.views.base.cables_view.get_librenms_sync_device",
+                return_value=None,
+            ) as mock_sync_device,
+            patch("netbox_librenms_plugin.views.base.cables_view.cache") as mock_cache,
+        ):
+            mock_device = MagicMock()
+            mock_get_obj.return_value = mock_device
+            mock_cache.get.return_value = None  # No cached data
+
+            view.post(request)
+
+            # get_librenms_sync_device should be called with the posted server_key
+            mock_sync_device.assert_called_once_with(mock_device, server_key="production")
+            # cache lookup must also use the posted server_key (not the api default)
+            cache_key_arg = mock_cache.get.call_args[0][0]
+            assert "production" in cache_key_arg
+
+    def test_fallback_to_api_server_key(self):
+        """When POST body has no server_key, falls back to self.librenms_api.server_key."""
+        import json
+
+        from netbox_librenms_plugin.views.base.cables_view import SingleCableVerifyView
+
+        view = object.__new__(SingleCableVerifyView)
+        view._librenms_api = MagicMock()
+        view._librenms_api.server_key = "fallback-server"
+
+        request = MagicMock()
+        request.body = json.dumps(
+            {
+                "device_id": 1,
+                "local_port_id": "42",
+            }
+        ).encode()
+
+        with (
+            patch("netbox_librenms_plugin.views.base.cables_view.get_object_or_404") as mock_get_obj,
+            patch(
+                "netbox_librenms_plugin.views.base.cables_view.get_librenms_sync_device",
+                return_value=None,
+            ) as mock_sync_device,
+            patch("netbox_librenms_plugin.views.base.cables_view.cache") as mock_cache,
+        ):
+            mock_get_obj.return_value = MagicMock()
+            mock_cache.get.return_value = None
+
+            view.post(request)
+
+            mock_sync_device.assert_called_once()
+            assert mock_sync_device.call_args[1]["server_key"] == "fallback-server"
+            # cache lookup must also use the fallback server_key
+            cache_key_arg = mock_cache.get.call_args[0][0]
+            assert "fallback-server" in cache_key_arg
+
+
+# ---------------------------------------------------------------------------
+# import_single_device — lazy validation passes api
+# ---------------------------------------------------------------------------
diff --git a/netbox_librenms_plugin/tests/test_vlan_sync.py b/netbox_librenms_plugin/tests/test_vlan_sync.py
index caaced6f91..de710a1157 100644
--- a/netbox_librenms_plugin/tests/test_vlan_sync.py
+++ b/netbox_librenms_plugin/tests/test_vlan_sync.py
@@ -459,3 +459,25 @@ def test_default_name_matches_is_true(self):
         from netbox_librenms_plugin.utils import get_vlan_sync_css_class
 
         assert get_vlan_sync_css_class(exists_in_netbox=True) == "text-success"
+
+
+class TestVlanEntryDictGuardInSync:
+    """Verify isinstance(vlan_entry, dict) guard works in parse_port_vlan_data."""
+
+    def test_mixed_vlans_data_only_dicts_parsed(self, mock_librenms_config):
+        """vlans array with non-dict entries: only dict entries produce VIDs."""
+        from netbox_librenms_plugin.librenms_api import LibreNMSAPI
+
+        api = LibreNMSAPI(server_key="default")
+
+        port_data = {
+            "port_id": 1,
+            "ifName": "GigabitEthernet0/0",
+            "ifDescr": "GigabitEthernet0/0",
+            "ifTrunk": "dot1Q",
+            "ifVlan": None,
+            "vlans": [{"vlan": 10, "untagged": 1}, "bad_entry", {"vlan": 20}],
+        }
+        result = api.parse_port_vlan_data(port_data)
+        assert result["untagged_vlan"] == 10
+        assert result["tagged_vlans"] == [20]
diff --git a/netbox_librenms_plugin/urls.py b/netbox_librenms_plugin/urls.py
index 9eafdb1dca..7634e130b8 100644
--- a/netbox_librenms_plugin/urls.py
+++ b/netbox_librenms_plugin/urls.py
@@ -30,6 +30,7 @@
     InterfaceTypeMappingView,
     LibreNMSImportView,
     LibreNMSSettingsView,
+    RemoveServerMappingView,
     SaveUserPrefView,
     SingleCableVerifyView,
     SingleInterfaceVerifyView,
@@ -52,6 +53,7 @@
     VMIPAddressTableView,
     VMLibreNMSSyncView,
     VMStatusListView,
+    ConvertLegacyLibreNMSIdView,
 )
 
 urlpatterns = [
@@ -221,6 +223,16 @@
         AssignVCSerialView.as_view(),
         name="assign_vc_serial",
     ),
+    path(
+        "devices/<int:pk>/remove-server-mapping/",
+        RemoveServerMappingView.as_view(),
+        name="remove_server_mapping",
+    ),
+    path(
+        "devices/<int:pk>/convert-legacy-id/",
+        ConvertLegacyLibreNMSIdView.as_view(),
+        name="convert_legacy_librenms_id",
+    ),
     path(
         "device-status/",
         DeviceStatusListView.as_view(),
diff --git a/netbox_librenms_plugin/utils.py b/netbox_librenms_plugin/utils.py
index 00dd425a01..c28f93e7c8 100644
--- a/netbox_librenms_plugin/utils.py
+++ b/netbox_librenms_plugin/utils.py
@@ -4,6 +4,7 @@
 
 from dcim.models import Device
 from django.core.exceptions import ObjectDoesNotExist
+from django.db.models import Q
 from django.http import HttpRequest
 from netbox.config import get_config
 from netbox.plugins import get_plugin_config
@@ -76,7 +77,7 @@ def get_virtual_chassis_member(device: Device, port_name: str) -> Device:
         return device
 
 
-def get_librenms_sync_device(device: Device) -> Optional[Device]:
+def get_librenms_sync_device(device: Device, server_key: str = None) -> Optional[Device]:
     """
     Determine which Virtual Chassis member should handle LibreNMS sync operations.
 
@@ -84,13 +85,17 @@ def get_librenms_sync_device(device: Device) -> Optional[Device]:
     should have the librenms_id custom field set and be used for sync operations.
 
     Priority order for selecting the sync device:
-    1. Any member with librenms_id custom field set (highest priority - already configured)
+    1. Any member with librenms_id custom field set for *server_key* (highest priority).
+       When *server_key* is None, matches any member that has any librenms_id set.
     2. Master device with primary IP (if master is designated)
     3. Any member with primary IP (fallback when no master or master lacks IP)
     4. Member with lowest vc_position (for error messages when no IPs configured)
 
     Args:
         device (Device): Any device in the virtual chassis.
+        server_key: LibreNMS server key used to resolve the correct librenms_id mapping.
+                    Pass None to match any member that has any librenms_id (e.g. in
+                    contexts where the active server is not known, such as table columns).
 
     Returns:
         Optional[Device]: The device that should handle LibreNMS sync, or None if
@@ -102,13 +107,32 @@ def get_librenms_sync_device(device: Device) -> Optional[Device]:
     vc = device.virtual_chassis
     all_members = vc.members.all()
 
-    # Priority 1: Check if ANY member has librenms_id configured.
-    # LibreNMS device IDs are auto-incremented from 1 (MySQL default), so 0 is never valid.
-    # Using a truthy check safely excludes 0, None, "", and other falsy non-IDs.
-    for member in all_members:
-        raw_cf = member.cf.get("librenms_id")
-        if raw_cf and not isinstance(raw_cf, bool):
-            return member
+    if server_key is not None:
+        # Priority 1: Prefer member with an explicit per-server dict mapping for server_key.
+        # This ensures a migrated device is preferred over one with a legacy bare-int ID.
+        for member in all_members:
+            raw_cf = member.cf.get("librenms_id")
+            if isinstance(raw_cf, dict):
+                val = raw_cf.get(server_key)
+                if val is not None and not isinstance(val, bool):
+                    return member
+
+        # Priority 2 (legacy fallback): Any member whose librenms_id resolves for this server
+        # (includes bare-int legacy IDs that are a universal fallback).
+        for member in all_members:
+            result = get_librenms_device_id(member, server_key, auto_save=False)
+            if result is not None:
+                return member
+    else:
+        # server_key is None: match any member that has any librenms_id set (any server).
+        # Used in contexts without an active server (e.g. device status table columns).
+        for member in all_members:
+            raw_cf = member.cf.get("librenms_id")
+            if isinstance(raw_cf, dict):
+                if any(v is not None and not isinstance(v, bool) for v in raw_cf.values()):
+                    return member
+            elif raw_cf:
+                return member
 
     # Priority 2: Use master device if it has primary IP
     if vc.master and vc.master.primary_ip:
@@ -195,7 +219,7 @@ def get_interface_name_field(request: Optional[HttpRequest] = None) -> str:
     return get_plugin_config("netbox_librenms_plugin", "interface_name_field")
 
 
-def match_librenms_hardware_to_device_type(hardware_name: str) -> dict:
+def match_librenms_hardware_to_device_type(hardware_name: str) -> dict | None:
     """
     Match LibreNMS hardware string to a NetBox DeviceType.
 
@@ -212,9 +236,35 @@ def match_librenms_hardware_to_device_type(hardware_name: str) -> dict:
     """
     from dcim.models import DeviceType
 
+    try:
+        from netbox_librenms_plugin.models import DeviceTypeMapping
+
+        _has_device_type_mapping = True
+    except ImportError:
+        _has_device_type_mapping = False
+
     if not hardware_name or hardware_name == "-":
         return {"matched": False, "device_type": None, "match_type": None}
 
+    # Check DeviceTypeMapping table first (when available)
+    if _has_device_type_mapping:
+        try:
+            mapping = DeviceTypeMapping.objects.get(librenms_hardware__iexact=hardware_name)
+            return {
+                "matched": True,
+                "device_type": mapping.netbox_device_type,
+                "match_type": "mapping",
+            }
+        except DeviceTypeMapping.DoesNotExist:
+            pass
+        except DeviceTypeMapping.MultipleObjectsReturned:
+            logger.warning(
+                "Multiple DeviceTypeMapping entries match hardware %r — skipping mapping lookup; "
+                "resolve the ambiguity by removing duplicate mappings.",
+                hardware_name,
+            )
+            return None
+
     # Try part number exact match
     try:
         device_type = DeviceType.objects.get(part_number__iexact=hardware_name)
@@ -453,3 +503,206 @@ def check_vlan_group_matches(
             netbox_gid = netbox_tagged_group_ids.get(vid)
             return netbox_gid == selected_group_id
     return True
+
+
+def get_librenms_device_id(obj, server_key: str = "default", *, auto_save: bool = True):
+    """
+    Get the LibreNMS device/port ID for a specific server from the JSON custom field.
+
+    Supports both the legacy integer format and the new multi-server JSON format::
+
+        Legacy:  librenms_id = 42              → returned as universal fallback for any server_key
+        New:     librenms_id = {"primary": 42} → returns 42 only for server_key="primary"
+
+    If the stored value (or the dict entry for server_key) is a string it is
+    normalised to ``int``.  When *auto_save* is ``True`` (the default) the
+    normalised value is written back so that subsequent DB queries can use a
+    plain integer without defensive ``str()`` casting.  Pass ``auto_save=False``
+    in read-only contexts (e.g. table renderers) to avoid triggering unintended
+    DB writes or signals.
+
+    Args:
+        obj: NetBox object with a ``librenms_id`` custom field.
+        server_key: LibreNMS server key (from plugin ``servers`` config).
+        auto_save: When True (default), persist any normalised value back to the DB.
+
+    Returns:
+        int or None
+    """
+    cf_value = obj.cf.get("librenms_id")
+    if cf_value is None:
+        return None
+    if isinstance(cf_value, int) and not isinstance(cf_value, bool):
+        # Legacy bare integer — universal fallback for any server to ensure
+        # devices imported before multi-server support remain discoverable.
+        return cf_value
+    if isinstance(cf_value, str):
+        # Someone stored a bare string (e.g., via NetBox UI/API) — normalise to int.
+        # Treated as a legacy universal fallback for any server.
+        try:
+            int_id = int(cf_value)
+        except (ValueError, TypeError):
+            return None
+        if auto_save:
+            obj.custom_field_data["librenms_id"] = int_id
+            obj.save(update_fields=["custom_field_data"])
+        return int_id
+    if isinstance(cf_value, dict):
+        value = cf_value.get(server_key)
+        if isinstance(value, bool):
+            return None
+        if isinstance(value, str):
+            # Normalise string-stored ID inside JSON dict and write back.
+            try:
+                value = int(value)
+            except (ValueError, TypeError):
+                return None
+            if auto_save:
+                cf_value[server_key] = value
+                obj.custom_field_data["librenms_id"] = cf_value
+                obj.save(update_fields=["custom_field_data"])
+            return value
+        if isinstance(value, int):
+            return value
+        return None
+    return None
+
+
+def set_librenms_device_id(obj, device_id, server_key: str = "default"):
+    """
+    Set the LibreNMS device/port ID for a specific server on the JSON custom field.
+
+    Does NOT silently migrate legacy bare-integer values to the dict format.
+    If the field contains a legacy bare integer (or a string that parses as an integer),
+    a warning is logged and the write is skipped; use the migration workflow instead.
+
+    Args:
+        obj: NetBox object with a ``librenms_id`` custom field.
+        device_id: LibreNMS device ID (integer).
+        server_key: LibreNMS server key (from plugin ``servers`` config).
+    """
+    if isinstance(device_id, bool):
+        logger.warning(
+            "librenms_id device_id is a boolean (%r) on %r; not storing.",
+            device_id,
+            obj,
+        )
+        return
+    cf_value = obj.custom_field_data.get("librenms_id") or {}
+    if isinstance(cf_value, int) and not isinstance(cf_value, bool):
+        logger.warning(
+            "librenms_id on %r has legacy bare integer %r; skipping write to prevent "
+            "silent migration. Use the migration workflow to convert.",
+            obj,
+            cf_value,
+        )
+        return
+    elif isinstance(cf_value, str):
+        try:
+            int(cf_value)
+            logger.warning(
+                "librenms_id on %r has legacy bare integer string %r; skipping write to "
+                "prevent silent migration. Use the migration workflow to convert.",
+                obj,
+                cf_value,
+            )
+            return
+        except (ValueError, TypeError):
+            logger.warning(
+                "librenms_id custom field has unexpected string %r on %r; resetting to empty dict.",
+                cf_value,
+                obj,
+            )
+            cf_value = {}
+    elif not isinstance(cf_value, dict):
+        logger.warning(
+            "librenms_id custom field has unexpected type %s on %r; resetting to empty dict.",
+            type(cf_value).__name__,
+            obj,
+        )
+        cf_value = {}
+    try:
+        cf_value[server_key] = int(device_id)
+    except (TypeError, ValueError):
+        logger.warning(
+            "librenms_id device_id %r is not a valid integer on %r; not storing.",
+            device_id,
+            obj,
+        )
+        return  # Don't persist an invalid entry
+    obj.custom_field_data["librenms_id"] = cf_value
+
+
+def find_by_librenms_id(model, librenms_id, server_key: str = "default"):
+    """
+    Return the first object of *model* whose ``librenms_id`` JSON field contains
+    *librenms_id* under *server_key*.
+
+    Also matches legacy records stored as a bare ``librenms_id`` integer or string
+    in ``custom_field_data``—these predate multi-server support and act as a
+    universal fallback for any *server_key*.
+
+    Args:
+        model: A Django model class (Device, VirtualMachine, Interface, …).
+        librenms_id: The LibreNMS device/port ID to look up.
+        server_key: LibreNMS server key (from plugin ``servers`` config).
+
+    Returns:
+        Model instance or None
+    """
+    if librenms_id is None:
+        return None
+    if isinstance(librenms_id, bool):
+        return None
+    try:
+        librenms_id = int(librenms_id)
+    except (ValueError, TypeError):
+        pass  # keep original; string queries will still match string-stored IDs
+    q = Q(**{f"custom_field_data__librenms_id__{server_key}": librenms_id})
+    # Also match when the namespaced value was stored as a string (e.g. {"production": "42"}).
+    q |= Q(**{f"custom_field_data__librenms_id__{server_key}": str(librenms_id)})
+    # Always include legacy bare-integer and bare-string IDs as a universal fallback.
+    # Legacy records were created before multi-server support; they should be visible
+    # regardless of which server is currently active.
+    q |= Q(custom_field_data__librenms_id=librenms_id)
+    q |= Q(custom_field_data__librenms_id=str(librenms_id))
+    return model.objects.filter(q).first()
+
+
+def migrate_legacy_librenms_id(obj, server_key: str = "default") -> bool:
+    """
+    Migrate a legacy bare-integer ``librenms_id`` custom field to the JSON dict format,
+    scoped to *server_key*.
+
+    Only performs the migration when the current value is a bare integer, i.e. a record
+    created before the multi-server JSON refactor.  The integer is assumed to belong to
+    the server identified by *server_key* (the caller must verify this, e.g. by confirming
+    that the LibreNMS device ID and serial number both match).
+
+    Does **not** call ``obj.save()`` — the caller is responsible for persisting the change.
+
+    Args:
+        obj: NetBox object with a ``librenms_id`` custom field.
+        server_key: LibreNMS server key the legacy integer should be scoped to.
+
+    Returns:
+        True if the value was migrated, False if it was already in the correct format.
+    """
+    cf_value = obj.custom_field_data.get("librenms_id")
+    if isinstance(cf_value, bool):
+        return False
+    if isinstance(cf_value, int):
+        int_value = cf_value
+    elif isinstance(cf_value, str) and cf_value.isdigit():
+        int_value = int(cf_value)
+    else:
+        return False
+    obj.custom_field_data["librenms_id"] = {server_key: int_value}
+    logger.info(
+        "Migrated legacy librenms_id %r → {%r: %d} on %r",
+        cf_value,
+        server_key,
+        int_value,
+        obj,
+    )
+    return True
diff --git a/netbox_librenms_plugin/views/__init__.py b/netbox_librenms_plugin/views/__init__.py
index df3beac79b..103900c6c0 100644
--- a/netbox_librenms_plugin/views/__init__.py
+++ b/netbox_librenms_plugin/views/__init__.py
@@ -52,7 +52,9 @@
 from .sync.cables import SyncCablesView  # noqa: F401
 from .sync.device_fields import (  # noqa: F401
     AssignVCSerialView,
+    ConvertLegacyLibreNMSIdView,
     CreateAndAssignPlatformView,
+    RemoveServerMappingView,
     UpdateDeviceNameView,
     UpdateDevicePlatformView,
     UpdateDeviceSerialView,
diff --git a/netbox_librenms_plugin/views/base/cables_view.py b/netbox_librenms_plugin/views/base/cables_view.py
index 50b0a908d8..affb0a20f4 100644
--- a/netbox_librenms_plugin/views/base/cables_view.py
+++ b/netbox_librenms_plugin/views/base/cables_view.py
@@ -4,6 +4,7 @@
 from django.contrib import messages
 from django.core.cache import cache
 from django.core.exceptions import MultipleObjectsReturned
+from django.db.models import Q
 from django.http import JsonResponse
 from django.middleware.csrf import get_token
 from django.shortcuts import get_object_or_404, render
@@ -20,6 +21,30 @@
 from netbox_librenms_plugin.views.mixins import CacheMixin, LibreNMSAPIMixin, LibreNMSPermissionMixin
 
 
+def _librenms_id_q(server_key: str, value) -> Q:
+    """
+    Return a combined Q matching JSON-field and legacy bare-int librenms_id.
+
+    Matches both integer and string representations to handle any stored format.
+    """
+    if isinstance(value, bool):
+        return Q(pk__isnull=True) & Q(pk__isnull=False)  # match nothing
+
+    q = Q(**{f"custom_field_data__librenms_id__{server_key}": value}) | Q(custom_field_data__librenms_id=value)
+    try:
+        int_val = int(value)
+        str_val = str(int_val)
+        if int_val != value:  # value was a string; also add the integer variant
+            q |= Q(**{f"custom_field_data__librenms_id__{server_key}": int_val})
+            q |= Q(custom_field_data__librenms_id=int_val)
+        if str_val != value:  # value was an integer; also add the string variant
+            q |= Q(**{f"custom_field_data__librenms_id__{server_key}": str_val})
+            q |= Q(custom_field_data__librenms_id=str_val)
+    except (TypeError, ValueError):
+        pass
+    return q
+
+
 class BaseCableTableView(LibreNMSPermissionMixin, LibreNMSAPIMixin, CacheMixin, View):
     """
     Base view for synchronizing cable information from LibreNMS.
@@ -40,7 +65,8 @@ def get_ip_address(self, obj):
 
     def get_ports_data(self, obj):
         """Get ports data without affecting cache"""
-        cached_data = cache.get(self.get_cache_key(obj, "ports"))
+        server_key = self.librenms_api.server_key
+        cached_data = cache.get(self.get_cache_key(obj, "ports", server_key))
         if cached_data:
             return cached_data
         success, data = self.librenms_api.get_ports(self.librenms_id)
@@ -55,13 +81,23 @@ def get_links_data(self, obj):
         if not success or "error" in data:
             return None
 
-        ports_data = self.get_ports_data(obj)
+        # TODO: local_port names are baked into the cache using the requesting
+        # user's interface_name_field preference.  Subsequent users with a
+        # different preference will see (and match against) the wrong label.
+        # Fix requires either rebuilding names per-request from local_port_id
+        # or partitioning the cache key by interface_name_field.
         interface_name_field = get_interface_name_field(getattr(self, "request", None))
-        local_ports_map = {
-            str(port["port_id"]): port.get(interface_name_field)
-            for port in ports_data.get("ports", [])
-            if port.get("port_id") and port.get(interface_name_field)
-        }
+        ports_data = self.get_ports_data(obj)
+        local_ports_map = {}
+        for port in ports_data.get("ports", []):
+            raw_port_id = port.get("port_id")
+            if raw_port_id is None:
+                continue
+            port_id = str(raw_port_id)
+            port_name = port.get(interface_name_field)
+            if port_name is None:
+                continue
+            local_ports_map[port_id] = port_name
 
         links = data.get("links", [])
         return [
@@ -76,12 +112,14 @@ def get_links_data(self, obj):
             for link in links
         ]
 
-    def get_device_by_id_or_name(self, remote_device_id, hostname):
+    def get_device_by_id_or_name(self, remote_device_id, hostname, server_key=None):
         """Try to find device in NetBox first by librenms_id custom field, then by name"""
+        if server_key is None:
+            server_key = self.librenms_api.server_key
         # First try matching by LibreNMS ID
-        if remote_device_id:
+        if remote_device_id is not None:
             try:
-                device = Device.objects.get(custom_field_data__librenms_id=remote_device_id)
+                device = Device.objects.get(_librenms_id_q(server_key, remote_device_id))
                 return device, True, None
             except Device.DoesNotExist:
                 pass
@@ -110,19 +148,27 @@ def get_device_by_id_or_name(self, remote_device_id, hostname):
                     False,
                     f"Multiple devices found with the same name: {hostname}.",
                 )
+        except MultipleObjectsReturned:
+            return (
+                None,
+                False,
+                f"Multiple devices found with the same name: {hostname}.",
+            )
 
-    def enrich_local_port(self, link, obj):
+    def enrich_local_port(self, link, obj, server_key=None):
         """Add local port URL if interface exists in NetBox"""
         if local_port := link.get("local_port"):
             interface = None
             local_port_id = link.get("local_port_id")
+            if server_key is None:
+                server_key = self.librenms_api.server_key
 
             if hasattr(obj, "virtual_chassis") and obj.virtual_chassis:
                 chassis_member = get_virtual_chassis_member(obj, local_port)
 
                 # First try to find interface by librenms_id
                 if local_port_id:
-                    interface = chassis_member.interfaces.filter(custom_field_data__librenms_id=local_port_id).first()
+                    interface = chassis_member.interfaces.filter(_librenms_id_q(server_key, local_port_id)).first()
 
                 # Only if librenms_id match fails, try matching by name
                 if not interface:
@@ -130,7 +176,7 @@ def enrich_local_port(self, link, obj):
             else:
                 # First try to find interface by librenms_id
                 if local_port_id:
-                    interface = obj.interfaces.filter(custom_field_data__librenms_id=local_port_id).first()
+                    interface = obj.interfaces.filter(_librenms_id_q(server_key, local_port_id)).first()
 
                 # Only if librenms_id match fails, try matching by name
                 if not interface:
@@ -140,11 +186,13 @@ def enrich_local_port(self, link, obj):
                 link["local_port_url"] = reverse("dcim:interface", args=[interface.pk])
                 link["netbox_local_interface_id"] = interface.pk
 
-    def enrich_remote_port(self, link, device):
+    def enrich_remote_port(self, link, device, server_key=None):
         """Add remote port URL if device and interface exist in NetBox"""
         if remote_port := link.get("remote_port"):
             netbox_remote_interface = None
             librenms_remote_port_id = link.get("remote_port_id")
+            if server_key is None:
+                server_key = self.librenms_api.server_key
 
             # Handle virtual chassis case
             if hasattr(device, "virtual_chassis") and device.virtual_chassis:
@@ -154,7 +202,7 @@ def enrich_remote_port(self, link, device):
                 # First try to find interface by librenms_id
                 if librenms_remote_port_id:
                     netbox_remote_interface = chassis_member.interfaces.filter(
-                        custom_field_data__librenms_id=librenms_remote_port_id
+                        _librenms_id_q(server_key, librenms_remote_port_id)
                     ).first()
 
                 # If not found by librenms_id, fall back to name matching on the correct chassis member
@@ -165,7 +213,7 @@ def enrich_remote_port(self, link, device):
                 # First try to find interface by librenms_id
                 if librenms_remote_port_id:
                     netbox_remote_interface = device.interfaces.filter(
-                        custom_field_data__librenms_id=librenms_remote_port_id
+                        _librenms_id_q(server_key, librenms_remote_port_id)
                     ).first()
 
                 # If not found by librenms_id, fall back to name matching
@@ -212,9 +260,11 @@ def check_cable_status(self, link):
 
         return link
 
-    def process_remote_device(self, link, remote_hostname, remote_device_id):
+    def process_remote_device(self, link, remote_hostname, remote_device_id, server_key=None):
         """Process remote device data and add remote device URL if device exists in NetBox"""
-        device, found, error_message = self.get_device_by_id_or_name(remote_device_id, remote_hostname)
+        device, found, error_message = self.get_device_by_id_or_name(
+            remote_device_id, remote_hostname, server_key=server_key
+        )
         if found:
             link.update(
                 {
@@ -222,7 +272,7 @@ def process_remote_device(self, link, remote_hostname, remote_device_id):
                     "netbox_remote_device_id": device.pk,
                 }
             )
-            return self.enrich_remote_port(link, device)
+            return self.enrich_remote_port(link, device, server_key=server_key)
 
         link.update(
             {
@@ -233,14 +283,16 @@ def process_remote_device(self, link, remote_hostname, remote_device_id):
         )
         return link
 
-    def enrich_links_data(self, links_data, obj):
+    def enrich_links_data(self, links_data, obj, server_key=None):
         """Enrich links data with local and remote port URLs and cable status."""
         for link in links_data:
-            self.enrich_local_port(link, obj)
+            self.enrich_local_port(link, obj, server_key=server_key)
             link["device_id"] = obj.id
 
             if remote_hostname := link.get("remote_device"):
-                link = self.process_remote_device(link, remote_hostname, link.get("remote_device_id"))
+                link = self.process_remote_device(
+                    link, remote_hostname, link.get("remote_device_id"), server_key=server_key
+                )
                 if link.get("netbox_remote_device_id"):
                     link = self.check_cable_status(link)
 
@@ -249,12 +301,14 @@ def enrich_links_data(self, links_data, obj):
     def get_table(self, data, obj):
         """Get the table instance for the view."""
         table = super().get_table(data, obj)
-        table.htmx_url = f"{self.request.path}?tab=cables"
+        server_key = self.librenms_api.server_key
+        table.htmx_url = f"{self.request.path}?tab=cables" + (f"&server_key={server_key}" if server_key else "")
         return table
 
     def _prepare_context(self, request, obj, fetch_fresh=False):
         """Helper method to prepare the context data for cable sync views."""
         cache_expiry = None
+        server_key = self.librenms_api.server_key
 
         if fetch_fresh:
             # Always fetch new data when requested
@@ -263,7 +317,7 @@ def _prepare_context(self, request, obj, fetch_fresh=False):
                 return None
         else:
             # Try to use cached data
-            cached_links_data = cache.get(self.get_cache_key(obj, "links"))
+            cached_links_data = cache.get(self.get_cache_key(obj, "links", server_key))
             if cached_links_data:
                 links_data = cached_links_data.get("links", [])
             else:
@@ -284,10 +338,10 @@ def _prepare_context(self, request, obj, fetch_fresh=False):
             links_data = [{k: v for k, v in link.items() if k in _raw_keys} for link in links_data]
 
         # Enrich data in both cases to ensure current NetBox state
-        links_data = self.enrich_links_data(links_data, obj)
+        links_data = self.enrich_links_data(links_data, obj, server_key=server_key)
 
         # Cache after enrichment so verify/sync views read current NetBox state
-        cache_key = self.get_cache_key(obj, "links")
+        cache_key = self.get_cache_key(obj, "links", server_key)
         if fetch_fresh:
             cache.set(
                 cache_key,
@@ -302,7 +356,7 @@ def _prepare_context(self, request, obj, fetch_fresh=False):
 
         # Calculate cache expiry
         cache_ttl = cache.ttl(cache_key)
-        if cache_ttl is not None:
+        if cache_ttl is not None and cache_ttl > 0:
             cache_expiry = timezone.now() + timezone.timedelta(seconds=cache_ttl)
 
         table = self.get_table(links_data, obj)
@@ -312,6 +366,7 @@ def _prepare_context(self, request, obj, fetch_fresh=False):
             "table": table,
             "object": obj,
             "cache_expiry": cache_expiry,
+            "server_key": server_key,
         }
 
     def get_context_data(self, request, obj):
@@ -319,7 +374,7 @@ def get_context_data(self, request, obj):
         context = self._prepare_context(request, obj, fetch_fresh=False)
         if context is None:
             # No data found; return context with empty table
-            context = {"table": None, "object": obj, "cache_expiry": None}
+            context = {"table": None, "object": obj, "cache_expiry": None, "server_key": self.librenms_api.server_key}
         return context
 
     def post(self, request, pk):
@@ -332,7 +387,14 @@ def post(self, request, pk):
             return render(
                 request,
                 self.partial_template_name,
-                {"cable_sync": {"object": obj, "table": None, "cache_expiry": None}},
+                {
+                    "cable_sync": {
+                        "object": obj,
+                        "table": None,
+                        "cache_expiry": None,
+                        "server_key": self.librenms_api.server_key,
+                    }
+                },
             )
 
         messages.success(request, "Cable data refreshed successfully.")
@@ -352,6 +414,8 @@ def post(self, request):
         data = json.loads(request.body)
         selected_device_id = data.get("device_id")
         local_port_id = data.get("local_port_id")
+        # Read server_key from POST so we use the exact server the user was viewing
+        server_key = data.get("server_key") or self.librenms_api.server_key
 
         formatted_row = {
             "local_port": "",
@@ -364,16 +428,11 @@ def post(self, request):
         if selected_device_id:
             selected_device = get_object_or_404(Device, pk=selected_device_id)
 
-            # Resolve the VC device that holds cached LibreNMS data
-            if selected_device.virtual_chassis:
-                primary_device = get_librenms_sync_device(selected_device)
-            else:
-                primary_device = selected_device
-
-            if not primary_device:
-                return JsonResponse({"status": "success", "formatted_row": formatted_row})
+            # Use the same sync-device resolution as the GET path so the cache
+            # key matches what _prepare_context wrote.
+            primary_device = get_librenms_sync_device(selected_device, server_key=server_key) or selected_device
 
-            cached_links = cache.get(self.get_cache_key(primary_device, "links"))
+            cached_links = cache.get(self.get_cache_key(primary_device, "links", server_key))
 
             if cached_links:
                 link_data = next(
@@ -401,13 +460,14 @@ def post(self, request):
                     remote_hostname = link_data.get("remote_device", "")
                     if remote_hostname:
                         link_data = self.process_remote_device(
-                            link_data, remote_hostname, link_data.get("remote_device_id")
+                            link_data, remote_hostname, link_data.get("remote_device_id"), server_key=server_key
                         )
 
                     local_port = link_data.get("local_port", "")
                     formatted_row["local_port"] = local_port
 
                     # First try to find interface by librenms_id (handle VC members)
+                    _sk = server_key
                     interface = None
                     lookup_device = selected_device
                     if local_port and hasattr(selected_device, "virtual_chassis") and selected_device.virtual_chassis:
@@ -415,9 +475,7 @@ def post(self, request):
                         if chassis_member:
                             lookup_device = chassis_member
                     if local_port_id:
-                        interface = lookup_device.interfaces.filter(
-                            custom_field_data__librenms_id=local_port_id
-                        ).first()
+                        interface = lookup_device.interfaces.filter(_librenms_id_q(_sk, local_port_id)).first()
 
                     # If not found by librenms_id, try matching by name
                     if not interface and local_port:
@@ -459,10 +517,16 @@ def post(self, request):
 
                         if link_data.get("can_create_cable"):
                             csrf_token = get_token(request)
+                            server_key_input = (
+                                f'<input type="hidden" name="server_key" value="{escape(str(server_key))}">'
+                                if server_key
+                                else ""
+                            )
                             formatted_row["actions"] = f"""
                                 <form method="post" action="{reverse("plugins:netbox_librenms_plugin:sync_device_cables", args=[selected_device.id])}">
                                     <input type="hidden" name="csrfmiddlewaretoken" value="{csrf_token}">
                                     <input type="hidden" name="select" value="{escape(str(local_port_id))}">
+                                    {server_key_input}
                                     <button type="submit" class="btn btn-sm btn-primary">Sync Cable</button>
                                 </form>
                             """
diff --git a/netbox_librenms_plugin/views/base/interfaces_view.py b/netbox_librenms_plugin/views/base/interfaces_view.py
index 80e413a8f3..995e698c87 100644
--- a/netbox_librenms_plugin/views/base/interfaces_view.py
+++ b/netbox_librenms_plugin/views/base/interfaces_view.py
@@ -93,22 +93,23 @@ def post(self, request, pk):
         enriched_ports = self._enrich_ports_with_vlan_data(ports, interface_name_field)
         librenms_data["ports"] = enriched_ports
 
-        # Store data in cache
+        _server_key = self.librenms_api.server_key
+        # Store data in cache (keyed by server to avoid cross-server collisions)
         cache.set(
-            self.get_cache_key(obj, "ports"),
+            self.get_cache_key(obj, "ports", _server_key),
             librenms_data,
             timeout=self.librenms_api.cache_timeout,
         )
         last_fetched = timezone.now()
         cache.set(
-            self.get_last_fetched_key(obj, "ports"),
+            self.get_last_fetched_key(obj, "ports", _server_key),
             last_fetched,
             timeout=self.librenms_api.cache_timeout,
         )
 
         messages.success(request, "Interface data refreshed successfully.")
 
-        context = self.get_context_data(request, obj, interface_name_field)
+        context = self.get_context_data(request, obj, interface_name_field, _server_key)
         context = {"interface_sync": context}
         context["interface_name_field"] = interface_name_field
 
@@ -138,7 +139,7 @@ def _enrich_ports_with_vlan_data(self, ports, interface_name_field):
             enriched.append(port)
         return enriched
 
-    def get_context_data(self, request, obj, interface_name_field):
+    def get_context_data(self, request, obj, interface_name_field, server_key=None):
         """Get the context data for the interface sync view."""
         ports_data = []
         table = None
@@ -147,15 +148,18 @@ def get_context_data(self, request, obj, interface_name_field):
         if interface_name_field is None:
             interface_name_field = get_interface_name_field(request)
 
-        cached_data = cache.get(self.get_cache_key(obj, "ports"))
-        last_fetched = cache.get(self.get_last_fetched_key(obj, "ports"))
+        if server_key is None:
+            server_key = getattr(self.librenms_api, "server_key", None)
+
+        cached_data = cache.get(self.get_cache_key(obj, "ports", server_key))
+        last_fetched = cache.get(self.get_last_fetched_key(obj, "ports", server_key))
 
         # Get VLAN groups for dropdown
         vlan_groups = self.get_vlan_groups_for_device(obj)
         lookup_maps = self._build_vlan_lookup_maps(vlan_groups)
 
         # Load any user VLAN group overrides from cache (set by "apply to all")
-        vlan_group_overrides = cache.get(self.get_vlan_overrides_key(obj)) or {}
+        vlan_group_overrides = cache.get(self.get_vlan_overrides_key(obj, server_key)) or {}
 
         if cached_data:
             ports_data = cached_data.get("ports", [])
@@ -244,8 +248,10 @@ def get_context_data(self, request, obj, interface_name_field):
         if hasattr(obj, "virtual_chassis") and obj.virtual_chassis:
             virtual_chassis_members = obj.virtual_chassis.members.all()
 
-        cache_ttl = cache.ttl(self.get_cache_key(obj, "ports"))
-        cache_expiry = timezone.now() + timezone.timedelta(seconds=cache_ttl) if cache_ttl is not None else None
+        cache_ttl = cache.ttl(self.get_cache_key(obj, "ports", server_key))
+        cache_expiry = (
+            timezone.now() + timezone.timedelta(seconds=cache_ttl) if cache_ttl is not None and cache_ttl > 0 else None
+        )
 
         return {
             "object": obj,
@@ -256,6 +262,7 @@ def get_context_data(self, request, obj, interface_name_field):
             "virtual_chassis_members": virtual_chassis_members,
             "interface_name_field": interface_name_field,
             "netbox_only_interfaces": netbox_only_interfaces,
+            "server_key": server_key,
         }
 
     def _add_vlan_group_selection(self, port, lookup_maps, device, vlan_group_overrides=None):
diff --git a/netbox_librenms_plugin/views/base/ip_addresses_view.py b/netbox_librenms_plugin/views/base/ip_addresses_view.py
index 22f4b49742..b5d80bc162 100644
--- a/netbox_librenms_plugin/views/base/ip_addresses_view.py
+++ b/netbox_librenms_plugin/views/base/ip_addresses_view.py
@@ -11,7 +11,7 @@
 from virtualization.models import VirtualMachine
 
 from netbox_librenms_plugin.tables.ipaddresses import IPAddressTable
-from netbox_librenms_plugin.utils import get_interface_name_field
+from netbox_librenms_plugin.utils import get_interface_name_field, get_librenms_device_id
 from netbox_librenms_plugin.views.mixins import CacheMixin, LibreNMSAPIMixin, LibreNMSPermissionMixin
 
 
@@ -104,11 +104,12 @@ def _prefetch_netbox_data(self, obj):
         all_interfaces = list(obj.interfaces.all())
 
         # Create maps for efficient lookups
-        interfaces_by_librenms_id = {
-            interface.custom_field_data.get("librenms_id"): interface
-            for interface in all_interfaces
-            if interface.custom_field_data.get("librenms_id")
-        }
+        server_key = self.librenms_api.server_key
+        interfaces_by_librenms_id = {}
+        for interface in all_interfaces:
+            lib_id = get_librenms_device_id(interface, server_key, auto_save=False)
+            if lib_id is not None:
+                interfaces_by_librenms_id[str(lib_id)] = interface
 
         interfaces_by_name = {interface.name: interface for interface in all_interfaces}
 
@@ -191,8 +192,8 @@ def _enrich_existing_ip(self, enriched_ip, ip_address, port_id, librenms_interfa
         assigned_interface = ip_address.assigned_object
 
         # Check if interface matches by LibreNMS ID
-        if port_id in prefetched_data["interfaces_by_librenms_id"]:
-            interface = prefetched_data["interfaces_by_librenms_id"][port_id]
+        if str(port_id) in prefetched_data["interfaces_by_librenms_id"]:
+            interface = prefetched_data["interfaces_by_librenms_id"][str(port_id)]
             if assigned_interface == interface:
                 enriched_ip["status"] = "matched"
                 return
@@ -207,8 +208,8 @@ def _enrich_existing_ip(self, enriched_ip, ip_address, port_id, librenms_interfa
     def _add_interface_info_to_ip(self, enriched_ip, port_id, librenms_interface_name, prefetched_data):
         """Add interface information to the IP entry regardless of IP status"""
         # First try to match by LibreNMS ID (highest priority)
-        if port_id in prefetched_data["interfaces_by_librenms_id"]:
-            interface = prefetched_data["interfaces_by_librenms_id"][port_id]
+        if str(port_id) in prefetched_data["interfaces_by_librenms_id"]:
+            interface = prefetched_data["interfaces_by_librenms_id"][str(port_id)]
             enriched_ip["interface_name"] = interface.name
             enriched_ip["interface_url"] = interface.get_absolute_url()
             return
@@ -222,13 +223,15 @@ def _add_interface_info_to_ip(self, enriched_ip, port_id, librenms_interface_nam
     def get_table(self, data, obj, request):
         """Get the table instance for the view."""
         table = IPAddressTable(data)
-        table.htmx_url = f"{request.path}?tab=ipaddresses"
+        server_key = self.librenms_api.server_key
+        table.htmx_url = f"{request.path}?tab=ipaddresses" + (f"&server_key={server_key}" if server_key else "")
         return table
 
     def _prepare_context(self, request, obj, interface_name_field, fetch_fresh=False):
         """Helper method to prepare the context data for IP address sync views."""
         table = None
         cache_expiry = None
+        server_key = self.librenms_api.server_key
 
         if interface_name_field is None:
             interface_name_field = get_interface_name_field(request)
@@ -236,7 +239,7 @@ def _prepare_context(self, request, obj, interface_name_field, fetch_fresh=False
         if fetch_fresh:
             success, ip_data = self.get_ip_addresses(obj)
         else:
-            cached_ip_data = cache.get(self.get_cache_key(obj, "ip_addresses"))
+            cached_ip_data = cache.get(self.get_cache_key(obj, "ip_addresses", server_key))
             if cached_ip_data:
                 ip_data = cached_ip_data.get("ip_addresses", [])
             else:
@@ -248,14 +251,14 @@ def _prepare_context(self, request, obj, interface_name_field, fetch_fresh=False
         if fetch_fresh:
             # Cache the fresh data after enrichment
             cache.set(
-                self.get_cache_key(obj, "ip_addresses"),
+                self.get_cache_key(obj, "ip_addresses", server_key),
                 {"ip_addresses": ip_data},
                 timeout=self.librenms_api.cache_timeout,
             )
 
         # Calculate cache expiry
-        cache_ttl = cache.ttl(self.get_cache_key(obj, "ip_addresses"))
-        if cache_ttl is not None:
+        cache_ttl = cache.ttl(self.get_cache_key(obj, "ip_addresses", server_key))
+        if cache_ttl is not None and cache_ttl > 0:
             cache_expiry = timezone.now() + timezone.timedelta(seconds=cache_ttl)
 
         # Generate the table
@@ -268,6 +271,7 @@ def _prepare_context(self, request, obj, interface_name_field, fetch_fresh=False
             "table": table,
             "object": obj,
             "cache_expiry": cache_expiry,
+            "server_key": server_key,
         }
 
     def get_context_data(self, request, obj):
@@ -276,7 +280,7 @@ def get_context_data(self, request, obj):
         context = self._prepare_context(request, obj, interface_name_field, fetch_fresh=False)
         if context is None:
             # No data found; return context with empty table
-            context = {"table": None, "object": obj, "cache_expiry": None}
+            context = {"table": None, "object": obj, "cache_expiry": None, "server_key": self.librenms_api.server_key}
         return context
 
     def post(self, request, pk):
@@ -290,7 +294,14 @@ def post(self, request, pk):
             return render(
                 request,
                 self.partial_template_name,
-                {"ip_sync": {"object": obj, "table": None, "cache_expiry": None}},
+                {
+                    "ip_sync": {
+                        "object": obj,
+                        "table": None,
+                        "cache_expiry": None,
+                        "server_key": self.librenms_api.server_key,
+                    }
+                },
             )
 
         messages.success(request, "IP address data refreshed successfully.")
@@ -392,12 +403,6 @@ def _determine_status(self, exists_any_vrf, exists_specific_vrf, original_vrf_id
             else:
                 return "sync"
 
-    def _get_cache_key(self, obj, data_type):
-        """
-        Generate a cache key for the specified object and data type.
-        """
-        return f"librenms_plugin:{obj.__class__.__name__}:{obj.pk}:{data_type}"
-
     def post(self, request):
         """
         POST request to return json response with formatted IP address status.
@@ -408,6 +413,7 @@ def post(self, request):
             vrf_id = data.get("vrf_id")
             object_id = data.get("device_id")
             object_type = data.get("object_type")
+            server_key = data.get("server_key") or "default"
 
             if not ip_address:
                 return JsonResponse({"status": "error", "message": "No IP address provided"}, status=400)
@@ -427,7 +433,7 @@ def post(self, request):
             except ValueError as e:
                 return JsonResponse({"status": "error", "message": str(e)}, status=400)
 
-            cache_key = self._get_cache_key(obj, "ip_addresses")
+            cache_key = self.get_cache_key(obj, "ip_addresses", server_key)
             cached_data = cache.get(cache_key)
 
             # Basic record with default values
diff --git a/netbox_librenms_plugin/views/base/librenms_sync_view.py b/netbox_librenms_plugin/views/base/librenms_sync_view.py
index 15b51ad810..ad94988903 100644
--- a/netbox_librenms_plugin/views/base/librenms_sync_view.py
+++ b/netbox_librenms_plugin/views/base/librenms_sync_view.py
@@ -1,11 +1,13 @@
 import re
 
+from django.conf import settings as django_settings
 from django.shortcuts import get_object_or_404, render
 from netbox.views import generic
 
 from netbox_librenms_plugin.forms import AddToLIbreSNMPV1V2, AddToLIbreSNMPV3
 from netbox_librenms_plugin.utils import (
     get_interface_name_field,
+    get_librenms_device_id,
     get_librenms_sync_device,
     match_librenms_hardware_to_device_type,
 )
@@ -26,15 +28,20 @@ def get(self, request, pk, context=None):
         """Handle GET request for the LibreNMS sync view."""
         obj = get_object_or_404(self.model, pk=pk)
 
-        # For Virtual Chassis members, determine which device should handle LibreNMS sync.
-        # Always delegate to get_librenms_sync_device() which implements the full priority
-        # order (explicit per-server dict > legacy bare-int > master with IP > any IP > position).
+        # For Virtual Chassis members, always delegate to get_librenms_sync_device() so
+        # self._librenms_lookup_device and self.librenms_id are consistent with the
+        # helper-based VC status computed in get_context_data().  A legacy bare-int mapping
+        # on the viewed member must not shadow an explicit per-server mapping on another
+        # member — get_librenms_sync_device() applies the full priority order.
         librenms_lookup_device = obj
         if hasattr(obj, "virtual_chassis") and obj.virtual_chassis:
-            sync_device = get_librenms_sync_device(obj)
+            sync_device = get_librenms_sync_device(obj, server_key=self.librenms_api.server_key)
             if sync_device:
                 librenms_lookup_device = sync_device
 
+        # Store for use in get_context_data (badge generation needs the same object)
+        self._librenms_lookup_device = librenms_lookup_device
+
         # Get librenms_id using the determined lookup device
         self.librenms_id = self.librenms_api.get_librenms_id(librenms_lookup_device)
 
@@ -58,14 +65,17 @@ def get_context_data(self, request, obj):
 
         if hasattr(obj, "virtual_chassis") and obj.virtual_chassis:
             # Use helper function to determine the sync device
-            librenms_sync_device = get_librenms_sync_device(obj)
+            librenms_sync_device = get_librenms_sync_device(obj, server_key=self.librenms_api.server_key)
 
             # Determine sync device status
             sync_device_has_librenms_id = False
             sync_device_has_primary_ip = False
 
             if librenms_sync_device:
-                sync_device_has_librenms_id = bool(librenms_sync_device.cf.get("librenms_id"))
+                sync_device_has_librenms_id = (
+                    get_librenms_device_id(librenms_sync_device, self.librenms_api.server_key, auto_save=False)
+                    is not None
+                )
                 sync_device_has_primary_ip = bool(librenms_sync_device.primary_ip)
 
             context.update(
@@ -83,6 +93,7 @@ def get_context_data(self, request, obj):
         cable_context = self.get_cable_context(request, obj)
         ip_context = self.get_ip_context(request, obj)
         vlan_context = self.get_vlan_context(request, obj)
+        module_context = self.get_module_context(request, obj)
 
         interface_name_field = get_interface_name_field(request)
 
@@ -94,12 +105,27 @@ def get_context_data(self, request, obj):
 
         manufacturers = Manufacturer.objects.all().order_by("name")
 
+        # Detect legacy bare-int librenms_id format for conversion badge
+        _lookup_device = getattr(self, "_librenms_lookup_device", obj)
+        _raw_cf = _lookup_device.cf.get("librenms_id") if _lookup_device else None
+        librenms_id_is_legacy = (isinstance(_raw_cf, int) and not isinstance(_raw_cf, bool)) or (
+            isinstance(_raw_cf, str) and _raw_cf.isdigit()
+        )
+
+        # Determine if serial match allows legacy ID conversion
+        _librenms_serial = librenms_info["librenms_device_details"].get("librenms_device_serial", "-")
+        _netbox_serial = getattr(_lookup_device, "serial", "") or ""
+        librenms_id_serial_confirmed = bool(
+            _librenms_serial and _librenms_serial != "-" and _netbox_serial and _librenms_serial == _netbox_serial
+        )
+
         context.update(
             {
                 "interface_sync": interface_context,
                 "cable_sync": cable_context,
                 "ip_sync": ip_context,
                 "vlan_sync": vlan_context,
+                "module_sync": module_context,
                 "v1v2form": AddToLIbreSNMPV1V2(prefix="v1v2"),
                 "v3form": AddToLIbreSNMPV3(prefix="v3"),
                 "librenms_device_id": self.librenms_id,
@@ -111,11 +137,94 @@ def get_context_data(self, request, obj):
                 "platform_info": platform_info,
                 "vc_inventory_serials": librenms_info["librenms_device_details"].get("vc_inventory_serials", []),
                 "manufacturers": manufacturers,
+                "all_server_mappings": self._build_all_server_mappings(_lookup_device, self.librenms_api.server_key),
+                "librenms_id_is_legacy": librenms_id_is_legacy,
+                "librenms_id_serial_confirmed": librenms_id_serial_confirmed,
+                # Lookup device may differ from object (e.g. VC master vs member).
+                # Used by the Remove server mapping form to post to the correct device.
+                "lookup_device_pk": _lookup_device.pk if _lookup_device else obj.pk,
+                "lookup_device_model_name": (
+                    _lookup_device._meta.model_name if _lookup_device else obj._meta.model_name
+                ),
+                "object_model_name": obj._meta.model_name,
             }
         )
 
         return context
 
+    @staticmethod
+    def _build_all_server_mappings(obj, active_server_key):
+        """
+        Build a list of all LibreNMS server mappings for the given device.
+
+        Each entry describes one server<->ID mapping stored in the ``librenms_id``
+        custom field:
+
+        * ``server_key``    – the key as stored in the CF dict.
+        * ``display_name``  – human-readable name from PLUGINS_CONFIG, or the key.
+        * ``librenms_url``  – base URL of that server (``None`` when not configured).
+        * ``device_id``     – the integer device ID on that server.
+        * ``device_url``    – direct URL to the device page on that server (or ``None``).
+        * ``is_configured`` – True when the server key exists in current plugin config.
+        * ``is_active``     – True when this is the currently active server.
+
+        Returns ``None`` for legacy bare-int format (no per-server info to show)
+        and ``None`` when the CF is absent/invalid.
+        """
+        cf_value = obj.custom_field_data.get("librenms_id")
+        if not isinstance(cf_value, dict) or not cf_value:
+            return None
+
+        plugins_cfg = getattr(django_settings, "PLUGINS_CONFIG", {}).get("netbox_librenms_plugin", {})
+        servers_config = plugins_cfg.get("servers") or {}
+        if not isinstance(servers_config, dict):
+            servers_config = {}
+
+        result = []
+        for sk, did in cf_value.items():
+            # Validate device ID — accept int or digit-string, skip bool/None/junk.
+            if isinstance(did, bool) or did is None:
+                continue
+            if isinstance(did, str):
+                if not did.isdigit():
+                    continue
+                did = int(did)
+            elif not isinstance(did, int):
+                continue
+            srv_cfg = servers_config.get(sk)
+            # Legacy single-server config: "default" key with no matching servers entry —
+            # fall back to root-level librenms_url/display_name in plugins_cfg.
+            if srv_cfg is None and sk == "default":
+                legacy_url = plugins_cfg.get("librenms_url")
+                if legacy_url:
+                    srv_cfg = {
+                        "librenms_url": legacy_url,
+                        "display_name": plugins_cfg.get("display_name") or f"Default Server ({legacy_url})",
+                    }
+            is_configured = srv_cfg is not None
+            # Treat malformed (non-dict) server config entries as unconfigured
+            if srv_cfg is not None and not isinstance(srv_cfg, dict):
+                srv_cfg = None
+                is_configured = False
+            librenms_url = srv_cfg.get("librenms_url") if srv_cfg else None
+            display_name = (srv_cfg.get("display_name") or sk) if srv_cfg else sk
+            device_url = f"{librenms_url}/device/device={did}/" if librenms_url else None
+            result.append(
+                {
+                    "server_key": sk,
+                    "display_name": display_name,
+                    "librenms_url": librenms_url,
+                    "device_id": did,
+                    "device_url": device_url,
+                    "is_configured": is_configured,
+                    "is_active": sk == active_server_key,
+                }
+            )
+
+        # Sort: active first, then configured, then orphaned
+        result.sort(key=lambda e: 0 if e["is_active"] else (1 if e["is_configured"] else 2))
+        return result or None
+
     def get_librenms_device_info(self, obj):
         """Get the LibreNMS device information for the given object."""
         found_in_librenms = False
@@ -265,6 +374,13 @@ def get_vlan_context(self, request, obj):
         """
         return None
 
+    def get_module_context(self, request, obj):
+        """
+        Get the context data for module sync.
+        Subclasses should override this method if applicable (e.g. VMs return None).
+        """
+        return None
+
     @staticmethod
     def _strip_vc_pattern(name):
         """
diff --git a/netbox_librenms_plugin/views/base/vlan_table_view.py b/netbox_librenms_plugin/views/base/vlan_table_view.py
index 78bbfb0fca..62c6bd7a5c 100644
--- a/netbox_librenms_plugin/views/base/vlan_table_view.py
+++ b/netbox_librenms_plugin/views/base/vlan_table_view.py
@@ -64,13 +64,14 @@ def _fetch_and_cache_vlan_data(self, obj):
             return False, f"Failed to fetch VLANs: {vlans_data}"
 
         # Cache VLANs
+        server_key = self.librenms_api.server_key
         cache.set(
-            self.get_cache_key(obj, "vlans"),
+            self.get_cache_key(obj, "vlans", server_key),
             vlans_data,
             timeout=self.librenms_api.cache_timeout,
         )
         cache.set(
-            self.get_last_fetched_key(obj, "vlans"),
+            self.get_last_fetched_key(obj, "vlans", server_key),
             timezone.now(),
             timeout=self.librenms_api.cache_timeout,
         )
@@ -88,8 +89,9 @@ def get_vlan_context(self, request, obj):
         vlan_table = None
 
         # Get cached data
-        cached_vlans = cache.get(self.get_cache_key(obj, "vlans"))
-        last_fetched = cache.get(self.get_last_fetched_key(obj, "vlans"))
+        server_key = getattr(self.librenms_api, "server_key", None)
+        cached_vlans = cache.get(self.get_cache_key(obj, "vlans", server_key))
+        last_fetched = cache.get(self.get_last_fetched_key(obj, "vlans", server_key))
 
         # Get available VLAN groups for this device
         vlan_groups = self.get_vlan_groups_for_device(obj)
@@ -105,8 +107,8 @@ def get_vlan_context(self, request, obj):
             vlan_table.configure(request)
 
         # Calculate cache TTL
-        cache_ttl = cache.ttl(self.get_cache_key(obj, "vlans"))
-        cache_expiry = timezone.now() + timezone.timedelta(seconds=cache_ttl) if cache_ttl else None
+        cache_ttl = cache.ttl(self.get_cache_key(obj, "vlans", server_key))
+        cache_expiry = timezone.now() + timezone.timedelta(seconds=cache_ttl) if cache_ttl and cache_ttl > 0 else None
 
         return {
             "object": obj,
@@ -114,6 +116,7 @@ def get_vlan_context(self, request, obj):
             "vlan_groups": vlan_groups,
             "last_fetched": last_fetched,
             "cache_expiry": cache_expiry,
+            "server_key": server_key,
         }
 
     def _get_error_context(self, obj, error_message):
@@ -123,6 +126,7 @@ def _get_error_context(self, obj, error_message):
             "error_message": error_message,
             "vlan_table": None,
             "vlan_groups": self.get_vlan_groups_for_device(obj),
+            "server_key": getattr(self.librenms_api, "server_key", None),
         }
 
     def compare_vlans(self, librenms_vlans, lookup_maps=None, device=None):
diff --git a/netbox_librenms_plugin/views/imports/actions.py b/netbox_librenms_plugin/views/imports/actions.py
index d7023d7603..3064cd1f95 100644
--- a/netbox_librenms_plugin/views/imports/actions.py
+++ b/netbox_librenms_plugin/views/imports/actions.py
@@ -6,6 +6,8 @@
 from django.contrib import messages
 from django.core.cache import cache
 from django.core.exceptions import PermissionDenied, ValidationError
+from django.db import transaction
+
 from django.http import HttpResponse, JsonResponse
 from django.shortcuts import redirect, render
 from django.utils.html import escape
@@ -30,7 +32,7 @@
     fetch_model_by_id,
 )
 from netbox_librenms_plugin.tables.device_status import DeviceImportTable
-from netbox_librenms_plugin.utils import get_user_pref, save_user_pref
+from netbox_librenms_plugin.utils import get_user_pref, save_user_pref, set_librenms_device_id
 from netbox_librenms_plugin.views.mixins import LibreNMSAPIMixin, LibreNMSPermissionMixin, NetBoxObjectPermissionMixin
 
 logger = logging.getLogger(__name__)
@@ -209,6 +211,7 @@ def get_validated_device_with_selections(self, device_id: int, request) -> tuple
             include_vc_detection=enable_vc,
             use_sysname=use_sysname,
             strip_domain=strip_domain,
+            server_key=self.librenms_api.server_key,
         )
         validation["import_as_vm"] = is_vm
 
@@ -356,6 +359,7 @@ def post(self, request):
                 api=self.librenms_api,
                 use_sysname=use_sysname,
                 strip_domain=strip_domain,
+                server_key=self.librenms_api.server_key,
             )
 
             # Mark validation with VC detection flag for proper URL generation in table
@@ -494,6 +498,7 @@ def post(self, request):  # noqa: PLR0912 - branching keeps responses explicit
             return HttpResponse("Invalid device identifier", status=400)
 
         use_sysname, strip_domain = _resolve_naming_preferences(request)
+        vc_detection_enabled = request.POST.get("enable_vc_detection") in ("on", "true", "1", "True")
         sync_options = {
             "sync_interfaces": request.POST.get("sync_interfaces") == "on",
             "sync_cables": request.POST.get("sync_cables") == "on",
@@ -579,6 +584,7 @@ def post(self, request):  # noqa: PLR0912 - branching keeps responses explicit
                     vm_imports=vm_imports,
                     server_key=self.librenms_api.server_key,
                     sync_options=sync_options,
+                    vc_detection_enabled=vc_detection_enabled,
                     manual_mappings_per_device=manual_mappings_per_device,
                     libre_devices_cache=libre_devices_cache,
                 )
@@ -641,6 +647,7 @@ def post(self, request):  # noqa: PLR0912 - branching keeps responses explicit
                     sync_options=sync_options,
                     manual_mappings_per_device=manual_mappings_per_device,  # type: ignore
                     libre_devices_cache=libre_devices_cache_sync,
+                    vc_detection_enabled=vc_detection_enabled,
                     user=request.user,  # Pass user for permission checks
                 )
 
@@ -724,6 +731,7 @@ def post(self, request):  # noqa: PLR0912 - branching keeps responses explicit
                         import_as_vm=is_vm,
                         api=None,  # No VC detection needed for already-imported devices
                         include_vc_detection=False,
+                        server_key=self.librenms_api.server_key,
                         use_sysname=sync_options.get("use_sysname", True),
                         strip_domain=sync_options.get("strip_domain", False),
                     )
@@ -806,12 +814,15 @@ def get(self, request, device_id):
             "validation": validation,
             "use_sysname": use_sysname,
             "strip_domain": strip_domain,
+            "server_key": self.librenms_api.server_key,
         }
 
         # Add sync comparison data for existing devices
         existing = validation.get("existing_device")
         if existing:
             context["sync_info"] = self._build_sync_info(libre_device, existing)
+            context["existing_id_servers"] = self._build_id_server_info(existing)
+            context["existing_device_model_name"] = existing._meta.model_name
 
         return render(
             request,
@@ -855,7 +866,7 @@ def _build_sync_info(libre_device, existing_device):
         device_type_synced = True
         librenms_device_type = None
         netbox_device_type = getattr(existing_device, "device_type", None)
-        if librenms_hardware and librenms_hardware != "-" and netbox_device_type is not None:
+        if librenms_hardware and librenms_hardware != "-":
             from netbox_librenms_plugin.utils import match_librenms_hardware_to_device_type
 
             hw_match = match_librenms_hardware_to_device_type(librenms_hardware)
@@ -881,6 +892,45 @@ def _build_sync_info(libre_device, existing_device):
             "all_synced": all_synced,
         }
 
+    @staticmethod
+    def _build_id_server_info(existing_device):
+        """
+        Return per-server ID mappings for the existing device's librenms_id custom field.
+
+        Returns a list of dicts with server_key, display_name, and device_id — one entry
+        per server the device is linked to. Returns None when the format is legacy (bare int)
+        or when the field is absent/invalid.
+        """
+        from django.conf import settings
+
+        cf_value = existing_device.custom_field_data.get("librenms_id")
+        if not isinstance(cf_value, dict):
+            return None
+
+        plugins_config = settings.PLUGINS_CONFIG.get("netbox_librenms_plugin") or {}
+        servers_config = plugins_config.get("servers") or {}
+        if not isinstance(servers_config, dict):
+            servers_config = {}
+        result = []
+        for sk, did in cf_value.items():
+            if isinstance(did, bool) or not isinstance(did, (int, str)):
+                continue
+            if isinstance(did, str):
+                if not did.isdigit():
+                    continue
+                did = int(did)
+            srv_cfg = servers_config.get(sk)
+            # Legacy single-server config: "default" key with no matching servers entry —
+            # fall back to root-level display_name in plugins_config.
+            if srv_cfg is None and sk == "default" and not servers_config:
+                display_name = plugins_config.get("display_name") or sk
+            else:
+                if not isinstance(srv_cfg, dict):
+                    srv_cfg = {}
+                display_name = srv_cfg.get("display_name") or sk
+            result.append({"server_key": sk, "display_name": display_name, "device_id": did})
+        return result or None
+
 
 class DeviceRoleUpdateView(LibreNMSPermissionMixin, LibreNMSAPIMixin, DeviceImportHelperMixin, View):
     """HTMX view to update a table row when a role is selected."""
@@ -932,20 +982,42 @@ def post(self, request, device_id):
             return error
 
         from dcim.models import Device
+        from netbox_librenms_plugin.librenms_api import LibreNMSAPI
 
         action = request.POST.get("action")
         existing_device_id = request.POST.get("existing_device_id")
+        existing_device_type = request.POST.get("existing_device_type", "device")
+
+        # If the form submitted a specific server_key, honour it so the handler uses
+        # the same server context as the import page when the user clicked the button.
+        post_server_key = request.POST.get("server_key", "").strip()
+        if post_server_key:
+            self._librenms_api = LibreNMSAPI(server_key=post_server_key)
 
         if not action or not existing_device_id:
             return HttpResponse("Missing action or existing_device_id", status=400)
 
+        # VirtualMachine is supported for migrate_librenms_id only; all other actions
+        # operate on Device-specific fields (serial, device_type) and remain Device-only.
+        if existing_device_type == "virtualmachine":
+            if action != "migrate_librenms_id":
+                return HttpResponse(
+                    f"Action '{escape(action)}' is not supported for virtual machines",
+                    status=400,
+                )
+            from virtualization.models import VirtualMachine as NetBoxVM
+
+            existing_model: type = NetBoxVM
+        else:
+            existing_model = Device
+
         try:
-            existing_device = Device.objects.get(pk=int(existing_device_id))
-        except (Device.DoesNotExist, ValueError):
+            existing_device = existing_model.objects.get(pk=int(existing_device_id))
+        except (existing_model.DoesNotExist, ValueError):
             return HttpResponse("Existing device not found", status=404)
 
-        # Object-level change permission for the specific device being mutated.
-        self.required_object_permissions = {"POST": [("change", Device)]}
+        # Object-level change permission for the specific model being mutated.
+        self.required_object_permissions = {"POST": [("change", existing_model)]}
         if error := self.require_object_permissions("POST"):
             return error
 
@@ -959,7 +1031,7 @@ def post(self, request, device_id):
         validated_existing = validation.get("existing_device") if validation else None
         if validated_existing is None:
             return HttpResponse("Missing validated conflict target", status=400)
-        if validated_existing.pk != existing_device.pk:
+        if validated_existing.pk != existing_device.pk or type(validated_existing) is not type(existing_device):
             return HttpResponse("Device ID mismatch: existing_device_id does not match validated device", status=400)
 
         # Require force flag when device type mismatches, but only for actions that use it
@@ -976,108 +1048,121 @@ def post(self, request, device_id):
             librenms_device_type = validation.get("device_type", {}).get("device_type")
 
         librenms_id = libre_device.get("device_id")
-
-        # Check for LibreNMS ID collision before any linking action
+        if isinstance(librenms_id, bool):
+            return HttpResponse("Invalid or missing LibreNMS device_id in payload", status=400)
+        try:
+            librenms_id = int(librenms_id)
+        except (TypeError, ValueError):
+            return HttpResponse("Invalid or missing LibreNMS device_id in payload", status=400)
+
+        # Wrap the LibreNMS-ID collision check and subsequent write in a single
+        # transaction so the read-then-write is atomic for link/update/update_serial.
+        # NOTE: A fully race-free guarantee would require a DB-unique constraint on
+        # (server_key, librenms_id) — e.g., a dedicated DeviceLibreNMSIDMapping model.
+        # That is deferred to a future schema migration.  Until then, we acquire a
+        # row-level lock on the target device before re-checking for conflicts, which
+        # serializes concurrent operations on the SAME device and greatly reduces the
+        # window for assigning the same ID to two DIFFERENT devices.
         if action in {"link", "update", "update_serial"}:
-            id_conflict = (
-                Device.objects.filter(custom_field_data__librenms_id=int(librenms_id))
-                .exclude(pk=existing_device.pk)
-                .first()
-            )
-            if id_conflict:
-                return HttpResponse(
-                    f"LibreNMS ID conflict: ID {escape(str(librenms_id))} is already assigned to device "
-                    f"'{escape(id_conflict.name)}' (ID: {id_conflict.pk})",
-                    status=409,
-                )
-
-        if action == "link":
-            # Link to LibreNMS and update name from LibreNMS data
-            resolved_name = validation.get("resolved_name")
-            hostname = (
-                resolved_name
-                if resolved_name
-                else _determine_device_name(
-                    libre_device,
-                    use_sysname=request.POST.get("use-sysname-toggle") == "on",
-                    strip_domain=request.POST.get("strip-domain-toggle") == "on",
-                )
-            )
-            existing_device.custom_field_data["librenms_id"] = int(librenms_id)
-            existing_device.name = hostname
-            if librenms_device_type:
-                existing_device.device_type = librenms_device_type
-            if err := _save_device(existing_device):
-                return err
-            logger.info(f"Linked device '{existing_device.name}' to LibreNMS ID {librenms_id}")
-
-        elif action == "update":
-            # Update hostname, serial, and link to LibreNMS
-            resolved_name = validation.get("resolved_name")
-            incoming_serial = libre_device.get("serial") or ""
-            hostname = (
-                resolved_name
-                if resolved_name
-                else _determine_device_name(
-                    libre_device,
-                    use_sysname=request.POST.get("use-sysname-toggle") == "on",
-                    strip_domain=request.POST.get("strip-domain-toggle") == "on",
-                )
-            )
-            existing_device.custom_field_data["librenms_id"] = int(librenms_id)
-            if incoming_serial and incoming_serial != "-":
-                conflict_device = Device.objects.filter(serial=incoming_serial).exclude(pk=existing_device.pk).first()
-                if conflict_device:
+            from netbox_librenms_plugin.utils import find_by_librenms_id
+
+            with transaction.atomic():
+                server_key = self.librenms_api.server_key
+                # Lock the target device row so concurrent requests for the same
+                # device are serialized.  The conflict check below is still a
+                # best-effort guard for different devices; a DB unique constraint
+                # would be needed for full protection.
+                try:
+                    existing_device = Device.objects.select_for_update().get(pk=existing_device.pk)
+                except Device.DoesNotExist:
                     return HttpResponse(
-                        f"Serial conflict: '{escape(incoming_serial)}' is already assigned to device "
-                        f"'{escape(conflict_device.name)}' (ID: {conflict_device.pk})",
+                        "Device no longer exists; it may have been deleted concurrently.",
                         status=409,
                     )
-                existing_device.serial = incoming_serial
-            existing_device.name = hostname
-            if librenms_device_type:
-                existing_device.device_type = librenms_device_type
-            if err := _save_device(existing_device):
-                return err
-            logger.info(
-                f"Updated device '{existing_device.name}': serial={incoming_serial}, "
-                f"linked to LibreNMS ID {librenms_id}"
-            )
-
-        elif action == "update_serial":
-            # Update only the serial and link to LibreNMS
-            incoming_serial = libre_device.get("serial") or ""
-            existing_device.custom_field_data["librenms_id"] = int(librenms_id)
-            if incoming_serial and incoming_serial != "-":
-                conflict_device = Device.objects.filter(serial=incoming_serial).exclude(pk=existing_device.pk).first()
-                if conflict_device:
+                id_conflict = find_by_librenms_id(Device, int(librenms_id), server_key)
+                if id_conflict and id_conflict.pk != existing_device.pk:
                     return HttpResponse(
-                        f"Serial conflict: '{escape(incoming_serial)}' is already assigned to device "
-                        f"'{escape(conflict_device.name)}' (ID: {conflict_device.pk})",
+                        f"LibreNMS ID conflict: ID {escape(str(librenms_id))} is already assigned to device "
+                        f"'{escape(id_conflict.name)}' (ID: {id_conflict.pk})",
                         status=409,
                     )
-                existing_device.serial = incoming_serial
-            if librenms_device_type:
-                existing_device.device_type = librenms_device_type
-            if err := _save_device(existing_device):
-                return err
-            logger.info(
-                f"Updated serial on device '{existing_device.name}' to {incoming_serial}, "
-                f"linked to LibreNMS ID {librenms_id}"
-            )
+
+                if action == "link":
+                    # Link to LibreNMS and update name from LibreNMS data
+                    hostname = _get_hostname_for_action(request, validation, libre_device)
+                    set_librenms_device_id(existing_device, librenms_id, self.librenms_api.server_key)
+                    existing_device.name = hostname
+                    if librenms_device_type:
+                        existing_device.device_type = librenms_device_type
+                    if err := _save_device(existing_device):
+                        return err
+                    logger.info(f"Linked device '{existing_device.name}' to LibreNMS ID {librenms_id}")
+
+                elif action == "update":
+                    # Update hostname, serial, and link to LibreNMS
+                    hostname = _get_hostname_for_action(request, validation, libre_device)
+                    incoming_serial = libre_device.get("serial") or ""
+                    if incoming_serial and incoming_serial != "-":
+                        # Lock any conflicting device under the same transaction to reduce
+                        # the serial-assignment race window (best-effort; a DB unique
+                        # constraint on serial would give full protection).
+                        conflict_device = (
+                            Device.objects.select_for_update()
+                            .filter(serial=incoming_serial)
+                            .exclude(pk=existing_device.pk)
+                            .first()
+                        )
+                        if conflict_device:
+                            return HttpResponse(
+                                f"Serial conflict: '{escape(incoming_serial)}' is already assigned to device "
+                                f"'{escape(conflict_device.name)}' (ID: {conflict_device.pk})",
+                                status=409,
+                            )
+                        existing_device.serial = incoming_serial
+                    existing_device.name = hostname
+                    if librenms_device_type:
+                        existing_device.device_type = librenms_device_type
+                    set_librenms_device_id(existing_device, librenms_id, self.librenms_api.server_key)
+                    if err := _save_device(existing_device):
+                        return err
+                    logger.info(
+                        f"Updated device '{existing_device.name}': serial={incoming_serial}, "
+                        f"linked to LibreNMS ID {librenms_id}"
+                    )
+
+                elif action == "update_serial":
+                    # Update only the serial and link to LibreNMS
+                    incoming_serial = libre_device.get("serial") or ""
+                    if incoming_serial and incoming_serial != "-":
+                        # Lock any conflicting device under the same transaction to reduce
+                        # the serial-assignment race window (best-effort; a DB unique
+                        # constraint on serial would give full protection).
+                        conflict_device = (
+                            Device.objects.select_for_update()
+                            .filter(serial=incoming_serial)
+                            .exclude(pk=existing_device.pk)
+                            .first()
+                        )
+                        if conflict_device:
+                            return HttpResponse(
+                                f"Serial conflict: '{escape(incoming_serial)}' is already assigned to device "
+                                f"'{escape(conflict_device.name)}' (ID: {conflict_device.pk})",
+                                status=409,
+                            )
+                        existing_device.serial = incoming_serial
+                    if librenms_device_type:
+                        existing_device.device_type = librenms_device_type
+                    set_librenms_device_id(existing_device, librenms_id, self.librenms_api.server_key)
+                    if err := _save_device(existing_device):
+                        return err
+                    logger.info(
+                        f"Updated serial on device '{existing_device.name}' to {incoming_serial}, "
+                        f"linked to LibreNMS ID {librenms_id}"
+                    )
 
         elif action == "sync_name":
             # Sync device name from LibreNMS (e.g., IP → sysName)
-            resolved_name = validation.get("resolved_name")
-            hostname = (
-                resolved_name
-                if resolved_name
-                else _determine_device_name(
-                    libre_device,
-                    use_sysname=request.POST.get("use-sysname-toggle") == "on",
-                    strip_domain=request.POST.get("strip-domain-toggle") == "on",
-                )
-            )
+            hostname = _get_hostname_for_action(request, validation, libre_device)
             existing_device.name = hostname
             if err := _save_device(existing_device):
                 return err
@@ -1094,25 +1179,41 @@ def post(self, request, device_id):
                 return HttpResponse("No LibreNMS device type available to update", status=400)
 
         elif action == "sync_serial":
-            # Sync serial number from LibreNMS
+            # Sync serial number from LibreNMS.
+            # Wrap conflict-check-and-write in a transaction with a row lock so
+            # concurrent requests cannot both pass the serial uniqueness guard.
             incoming_serial = libre_device.get("serial") or ""
             if incoming_serial and incoming_serial != "-":
-                # Check for serial ownership conflict
-                conflict_device = Device.objects.filter(serial=incoming_serial).exclude(pk=existing_device.pk).first()
-                if conflict_device:
-                    logger.warning(
-                        f"Serial sync blocked: '{incoming_serial}' already assigned to "
-                        f"'{conflict_device.name}' (pk={conflict_device.pk})"
-                    )
-                    return HttpResponse(
-                        f"Serial conflict: '{escape(incoming_serial)}' is already assigned to device "
-                        f"'{escape(conflict_device.name)}' (ID: {conflict_device.pk})",
-                        status=409,
-                    )
-                existing_device.serial = incoming_serial
-                if err := _save_device(existing_device):
-                    return err
-                logger.info(f"Synced serial on '{existing_device.name}' to {incoming_serial}")
+                with transaction.atomic():
+                    try:
+                        locked_device = Device.objects.select_for_update().get(pk=existing_device.pk)
+                    except Device.DoesNotExist:
+                        return HttpResponse(
+                            "Device no longer exists; it may have been deleted concurrently.",
+                            status=409,
+                        )
+                    # Re-check for serial ownership conflict under lock.
+                    # Note: We intentionally do NOT enforce a DB-level uniqueness constraint on
+                    # Device.serial. During device moves/replacements, multiple devices may
+                    # temporarily share a serial (old record gets updated later). A unique
+                    # constraint would block those valid workflows. Instead, we rely on this
+                    # in-transaction row-lock check to guard concurrent sync of the SAME serial,
+                    # and flag conflicts via a 409 response for the user to resolve manually.
+                    conflict_device = Device.objects.filter(serial=incoming_serial).exclude(pk=locked_device.pk).first()
+                    if conflict_device:
+                        logger.warning(
+                            f"Serial sync blocked: '{incoming_serial}' already assigned to "
+                            f"'{conflict_device.name}' (pk={conflict_device.pk})"
+                        )
+                        return HttpResponse(
+                            f"Serial conflict: '{escape(incoming_serial)}' is already assigned to device "
+                            f"'{escape(conflict_device.name)}' (ID: {conflict_device.pk})",
+                            status=409,
+                        )
+                    locked_device.serial = incoming_serial
+                    if err := _save_device(locked_device):
+                        return err
+                    logger.info(f"Synced serial on '{locked_device.name}' to {incoming_serial}")
             else:
                 return HttpResponse("No valid serial from LibreNMS", status=400)
 
@@ -1147,6 +1248,91 @@ def post(self, request, device_id):
             else:
                 return HttpResponse(f"No matching device type for '{escape(hardware)}'", status=400)
 
+        elif action == "migrate_librenms_id":
+            # Migrate legacy bare-integer librenms_id to the JSON dict format.
+            # Only safe when the integer matches the LibreNMS device ID for this server,
+            # confirmed by serial match (or explicit force).
+            from netbox_librenms_plugin.utils import migrate_legacy_librenms_id
+
+            # Verify that the import workflow flagged this device as needing migration,
+            # preventing direct POST bypass of the modal validation gate.
+            if not validation.get("librenms_id_needs_migration"):
+                return HttpResponse(
+                    "Device is not flagged for librenms_id migration.",
+                    status=400,
+                )
+            # Direct access needed to detect legacy integer format for migration prompt:
+            # LibreNMSAPI.get_librenms_id() returns an int in both formats; only the raw
+            # type check on custom_field_data reveals whether migration is needed.
+            cf_value = existing_device.custom_field_data.get("librenms_id")
+            if isinstance(cf_value, bool) or not (
+                isinstance(cf_value, int) or (isinstance(cf_value, str) and cf_value.isdigit())
+            ):
+                return HttpResponse(
+                    "Device librenms_id is already in JSON format; no migration needed.",
+                    status=400,
+                )
+            # Normalise string-digit to int for consistent comparison
+            cf_int = int(cf_value) if isinstance(cf_value, str) else cf_value
+            # Verify the stored legacy ID matches the active LibreNMS device_id so we don't
+            # migrate a stale/incorrect association to the wrong server mapping.
+            if cf_int != librenms_id:
+                return HttpResponse(
+                    f"Legacy librenms_id ({cf_int}) does not match the active device ID "
+                    f"({librenms_id}); cannot migrate safely.",
+                    status=400,
+                )
+            if not validation.get("serial_confirmed") and not force:
+                return HttpResponse(
+                    "Serial number not confirmed. Check the force checkbox to migrate without serial verification.",
+                    status=400,
+                )
+            with transaction.atomic():
+                try:
+                    locked_device = existing_model.objects.select_for_update().get(pk=existing_device.pk)
+                except existing_model.DoesNotExist:
+                    return HttpResponse(
+                        "Object no longer exists; it may have been deleted concurrently.",
+                        status=409,
+                    )
+                # Re-check under lock — another request may have already migrated it
+                cf_locked = locked_device.custom_field_data.get("librenms_id")
+                if isinstance(cf_locked, bool) or not (
+                    isinstance(cf_locked, int) or (isinstance(cf_locked, str) and cf_locked.isdigit())
+                ):
+                    return HttpResponse(
+                        "Device librenms_id is already in JSON format; no migration needed.",
+                        status=400,
+                    )
+                cf_locked_int = int(cf_locked) if isinstance(cf_locked, str) else cf_locked
+                if cf_locked_int != librenms_id:
+                    return HttpResponse(
+                        f"Legacy librenms_id changed under lock ({cf_locked_int} != {librenms_id}); cannot migrate safely.",
+                        status=400,
+                    )
+                # Check that no other object already owns this ID (server-scoped or legacy)
+                server_key = self.librenms_api.server_key
+                from netbox_librenms_plugin.utils import find_by_librenms_id
+
+                match = find_by_librenms_id(existing_model, cf_locked_int, server_key)
+                conflict = match is not None and match.pk != locked_device.pk
+                if conflict:
+                    return HttpResponse(
+                        f"Another device already has librenms_id {cf_locked_int} for server '{server_key}'; cannot migrate.",
+                        status=409,
+                    )
+                if not migrate_legacy_librenms_id(locked_device, self.librenms_api.server_key):
+                    return HttpResponse(
+                        "Migration failed: librenms_id could not be converted.",
+                        status=400,
+                    )
+                if err := _save_device(locked_device):
+                    return err
+            logger.info(
+                f"Migrated legacy librenms_id on '{locked_device.name}' "
+                f"to {{{self.librenms_api.server_key!r}: {cf_locked_int}}}"
+            )
+
         else:
             return HttpResponse(f"Unknown action: {escape(action)}", status=400)
 
diff --git a/netbox_librenms_plugin/views/imports/list.py b/netbox_librenms_plugin/views/imports/list.py
index cabd564c80..e3ec701d24 100644
--- a/netbox_librenms_plugin/views/imports/list.py
+++ b/netbox_librenms_plugin/views/imports/list.py
@@ -122,6 +122,10 @@ def _load_job_results(self, job_id):
 
         if not validated_devices and device_ids:
             logger.error(f"Job {job_id} cache expired. Processed {len(device_ids)} devices but none in cache.")
+        else:
+            # Mirror the job's naming settings so toggle state matches the cached results
+            self._use_sysname = use_sysname
+            self._strip_domain = strip_domain
 
         return validated_devices
 
@@ -142,10 +146,10 @@ def get(self, request, *args, **kwargs):  # noqa: D401 - inherited doc
         # queryset loading) use the same use_sysname/strip_domain values.
         # Cascade: user preference → plugin settings → defaults.
         try:
-            settings_obj, _ = LibreNMSSettings.objects.get_or_create()
+            settings_obj = LibreNMSSettings.objects.first()
         except Exception:
             logger.exception(
-                "Failed to get or create LibreNMSSettings during LibreNMS import for user %s",
+                "Failed to read LibreNMSSettings during LibreNMS import for user %s",
                 getattr(request, "user", None),
             )
             settings_obj = None
diff --git a/netbox_librenms_plugin/views/mixins.py b/netbox_librenms_plugin/views/mixins.py
index 75090c105f..62136017a1 100644
--- a/netbox_librenms_plugin/views/mixins.py
+++ b/netbox_librenms_plugin/views/mixins.py
@@ -288,32 +288,42 @@ class CacheMixin:
     A mixin class that provides caching functionality.
     """
 
-    def get_cache_key(self, obj, data_type="ports"):
+    def get_cache_key(self, obj, data_type="ports", server_key=None):
         """
         Get the cache key for the object.
 
         Args:
             obj: The object to cache data for
-            data_type: Type of data being cached ('ports' or 'links')
+            data_type: Type of data being cached ('ports', 'links', 'inventory', etc.)
+            server_key: Optional LibreNMS server key for namespacing per-server data
         """
         model_name = obj._meta.model_name
-        return f"librenms_{data_type}_{model_name}_{obj.pk}"
+        base = f"librenms_{data_type}_{model_name}_{obj.pk}"
+        if server_key:
+            return f"{base}_{server_key}"
+        return base
 
-    def get_last_fetched_key(self, obj, data_type="ports"):
+    def get_last_fetched_key(self, obj, data_type="ports", server_key=None):
         """
         Get the cache key for the last fetched time of the object.
         """
         model_name = obj._meta.model_name
-        return f"librenms_{data_type}_last_fetched_{model_name}_{obj.pk}"
+        base = f"librenms_{data_type}_last_fetched_{model_name}_{obj.pk}"
+        if server_key:
+            return f"{base}_{server_key}"
+        return base
 
-    def get_vlan_overrides_key(self, obj):
+    def get_vlan_overrides_key(self, obj, server_key=None):
         """
         Get the cache key for user VLAN group override selections.
 
         Stores a {vid_str: group_id_str} map so that "apply to all" VLAN
-        group choices persist across table pages.
+        group choices persist across table pages. Including server_key scopes
+        overrides per-server to avoid leakage when multiple servers are configured.
         """
         model_name = obj._meta.model_name
+        if server_key:
+            return f"librenms_vlan_group_overrides_{model_name}_{obj.pk}_{server_key}"
         return f"librenms_vlan_group_overrides_{model_name}_{obj.pk}"
 
 
@@ -413,11 +423,12 @@ def _build_vlan_lookup_maps(self, vlan_groups):
             group_id = group.pk if group else None
             name = vlan.name
 
-            # Build VID to groups lookup for ambiguity detection
-            if vid not in vid_to_groups:
-                vid_to_groups[vid] = []
-            if group and group not in vid_to_groups[vid]:
-                vid_to_groups[vid].append(group)
+            # Build VID to groups lookup for ambiguity detection (group VLANs only)
+            if group:
+                if vid not in vid_to_groups:
+                    vid_to_groups[vid] = []
+                if group not in vid_to_groups[vid]:
+                    vid_to_groups[vid].append(group)
 
             # Build (vid, group_id) to vlan lookup
             vid_group_to_vlan[(vid, group_id)] = vlan
@@ -559,7 +570,7 @@ def _get_vlan_groups_for_scope(self, model_class, objects):
             return VLANGroup.objects.none()
 
         content_type = ContentType.objects.get_for_model(model_class)
-        object_ids = [obj.pk for obj in objects if obj is not None]
+        object_ids = [obj.pk for obj in objects if obj is not None and obj.pk is not None]
 
         if not object_ids:
             return VLANGroup.objects.none()
diff --git a/netbox_librenms_plugin/views/object_sync/devices.py b/netbox_librenms_plugin/views/object_sync/devices.py
index 5859cc4a67..5b76a48cc9 100644
--- a/netbox_librenms_plugin/views/object_sync/devices.py
+++ b/netbox_librenms_plugin/views/object_sync/devices.py
@@ -31,7 +31,7 @@
 from ..base.ip_addresses_view import BaseIPAddressTableView
 from ..base.librenms_sync_view import BaseLibreNMSSyncView
 from ..base.vlan_table_view import BaseVLANTableView
-from ..mixins import CacheMixin, LibreNMSPermissionMixin
+from ..mixins import CacheMixin, LibreNMSAPIMixin, LibreNMSPermissionMixin
 
 
 @register_model_view(Device, name="librenms_sync", path="librenms-sync")
@@ -80,19 +80,28 @@ def get_redirect_url(self, obj):
 
     def get_table(self, data, obj, interface_name_field, vlan_groups=None):
         """Return the appropriate interface table, selecting VC variant if needed."""
+        server_key = self.librenms_api.server_key
         if hasattr(obj, "virtual_chassis") and obj.virtual_chassis:
             table = VCInterfaceTable(
-                data, device=obj, interface_name_field=interface_name_field, vlan_groups=vlan_groups
+                data,
+                device=obj,
+                interface_name_field=interface_name_field,
+                vlan_groups=vlan_groups,
+                server_key=server_key,
             )
         else:
             table = LibreNMSInterfaceTable(
-                data, device=obj, interface_name_field=interface_name_field, vlan_groups=vlan_groups
+                data,
+                device=obj,
+                interface_name_field=interface_name_field,
+                vlan_groups=vlan_groups,
+                server_key=server_key,
             )
-        table.htmx_url = f"{self.request.path}?tab=interfaces"
+        table.htmx_url = f"{self.request.path}?tab=interfaces" + (f"&server_key={server_key}" if server_key else "")
         return table
 
 
-class SingleInterfaceVerifyView(LibreNMSPermissionMixin, CacheMixin, View):
+class SingleInterfaceVerifyView(LibreNMSPermissionMixin, LibreNMSAPIMixin, CacheMixin, View):
     """Verify single interface data for a device via cached LibreNMS payload."""
 
     def post(self, request):
@@ -101,22 +110,19 @@ def post(self, request):
         selected_device_id = data.get("device_id")
         interface_name = data.get("interface_name")
         interface_name_field = data.get("interface_name_field") or get_interface_name_field()
+        server_key = data.get("server_key") or self.librenms_api.server_key
 
         if not selected_device_id:
             return JsonResponse({"status": "error", "message": "No device ID provided"}, status=400)
 
         selected_device = get_object_or_404(Device, pk=selected_device_id)
 
-        # Resolve the VC device that holds cached LibreNMS data
-        if selected_device.virtual_chassis:
-            primary_device = get_librenms_sync_device(selected_device)
-        else:
+        # Normalise to the VC sync device so cache keys match what the sync view stored
+        primary_device = get_librenms_sync_device(selected_device, server_key=server_key)
+        if primary_device is None:
             primary_device = selected_device
 
-        if not primary_device:
-            return JsonResponse({"status": "error", "message": "No sync device found for virtual chassis"}, status=404)
-
-        cached_data = cache.get(self.get_cache_key(primary_device, "ports"))
+        cached_data = cache.get(self.get_cache_key(primary_device, "ports", server_key))
 
         if cached_data:
             port_data = next(
@@ -311,7 +317,7 @@ def post(self, request):
         )
 
 
-class SaveVlanGroupOverridesView(LibreNMSPermissionMixin, CacheMixin, View):
+class SaveVlanGroupOverridesView(LibreNMSPermissionMixin, LibreNMSAPIMixin, CacheMixin, View):
     """
     Persist user VLAN-group-override selections in cache.
 
@@ -330,14 +336,20 @@ def post(self, request):
         data = json.loads(request.body)
         device_id = data.get("device_id")
         vid_group_map = data.get("vid_group_map", {})
+        server_key = data.get("server_key") or self.librenms_api.server_key
 
         if not device_id:
             return JsonResponse({"status": "error", "message": "No device ID provided"}, status=400)
 
         device = get_object_or_404(Device, pk=device_id)
 
+        # Normalise to the VC sync device so cache keys match what the sync view stored
+        sync_device = get_librenms_sync_device(device, server_key=server_key)
+        if sync_device is None:
+            sync_device = device
+
         # Use the remaining TTL of the ports cache so both expire together
-        ports_ttl = cache.ttl(self.get_cache_key(device, "ports"))
+        ports_ttl = cache.ttl(self.get_cache_key(sync_device, "ports", server_key))
         if ports_ttl is None or ports_ttl <= 0:
             return JsonResponse(
                 {"status": "error", "message": "No cached port data; refresh interfaces first"},
@@ -345,10 +357,10 @@ def post(self, request):
             )
 
         # Merge with any existing overrides (user may save multiple times)
-        existing = cache.get(self.get_vlan_overrides_key(device)) or {}
+        existing = cache.get(self.get_vlan_overrides_key(sync_device, server_key)) or {}
         existing.update(vid_group_map)
 
-        cache.set(self.get_vlan_overrides_key(device), existing, timeout=ports_ttl)
+        cache.set(self.get_vlan_overrides_key(sync_device, server_key), existing, timeout=ports_ttl)
 
         return JsonResponse({"status": "success"})
 
diff --git a/netbox_librenms_plugin/views/object_sync/vms.py b/netbox_librenms_plugin/views/object_sync/vms.py
index 354e1a3b5e..a7e9e42c8d 100644
--- a/netbox_librenms_plugin/views/object_sync/vms.py
+++ b/netbox_librenms_plugin/views/object_sync/vms.py
@@ -29,21 +29,17 @@ def get_interface_context(self, request, obj):
         interface_name_field = get_interface_name_field(request)
         interface_sync_view = VMInterfaceTableView()
         interface_sync_view.request = copy.copy(request)
-        return interface_sync_view.get_context_data(request, obj, interface_name_field)
+        return interface_sync_view.get_context_data(interface_sync_view.request, obj, interface_name_field)
 
     def get_cable_context(self, request, obj):
         """Return None; VMs do not support cable sync."""
         return None  # VMs do not expose cable sync data
 
-    def get_vlan_context(self, request, obj):
-        """VMs do not support VLAN sync."""
-        return None
-
     def get_ip_context(self, request, obj):
         """Return IP address sync context for the virtual machine."""
         ipaddress_sync_view = VMIPAddressTableView()
         ipaddress_sync_view.request = copy.copy(request)
-        return ipaddress_sync_view.get_context_data(request, obj)
+        return ipaddress_sync_view.get_context_data(ipaddress_sync_view.request, obj)
 
 
 class VMInterfaceTableView(BaseInterfaceTableView):
@@ -53,7 +49,13 @@ class VMInterfaceTableView(BaseInterfaceTableView):
 
     def get_table(self, data, obj, interface_name_field, vlan_groups=None):
         """Return a VM interface table for the given data."""
-        return LibreNMSVMInterfaceTable(data, device=obj, vlan_groups=vlan_groups)
+        return LibreNMSVMInterfaceTable(
+            data,
+            device=obj,
+            vlan_groups=vlan_groups,
+            server_key=self.librenms_api.server_key,
+            interface_name_field=interface_name_field,
+        )
 
     def get_interfaces(self, obj):
         """Return all interfaces for the virtual machine."""
diff --git a/netbox_librenms_plugin/views/sync/cables.py b/netbox_librenms_plugin/views/sync/cables.py
index f751426b47..473d34777f 100644
--- a/netbox_librenms_plugin/views/sync/cables.py
+++ b/netbox_librenms_plugin/views/sync/cables.py
@@ -1,3 +1,5 @@
+import logging
+
 from dcim.models import Cable, Device, Interface
 from django.contrib import messages
 from django.core.cache import cache
@@ -7,10 +9,17 @@
 from django.urls import reverse
 from django.views import View
 
-from netbox_librenms_plugin.views.mixins import CacheMixin, LibreNMSPermissionMixin, NetBoxObjectPermissionMixin
+from netbox_librenms_plugin.views.mixins import (
+    CacheMixin,
+    LibreNMSAPIMixin,
+    LibreNMSPermissionMixin,
+    NetBoxObjectPermissionMixin,
+)
+
+logger = logging.getLogger(__name__)
 
 
-class SyncCablesView(LibreNMSPermissionMixin, NetBoxObjectPermissionMixin, CacheMixin, View):
+class SyncCablesView(LibreNMSPermissionMixin, NetBoxObjectPermissionMixin, LibreNMSAPIMixin, CacheMixin, View):
     """Create NetBox cables using cached LibreNMS link data."""
 
     required_object_permissions = {
@@ -41,13 +50,19 @@ def get_selected_interfaces(self, request, initial_device):
 
     def get_cached_links_data(self, request, obj):
         """Return cached LibreNMS link data for the given object."""
-        cached_data = cache.get(self.get_cache_key(obj, "links"))
+        server_key = getattr(self, "_post_server_key", None) or self.librenms_api.server_key
+        cached_data = cache.get(self.get_cache_key(obj, "links", server_key))
         if not cached_data:
             return None
         return cached_data.get("links", [])
 
     def create_cable(self, local_interface, remote_interface, request):
-        """Create a cable between local and remote interfaces."""
+        """
+        Create a cable between local and remote interfaces.
+
+        Returns:
+            True on success, False on failure.
+        """
         try:
             Cable.objects.create(
                 a_terminations=[local_interface],
@@ -85,6 +100,8 @@ def process_single_interface(self, interface, cached_links):
         port_id = str(interface.get("local_port_id", ""))
         try:
             link_data = next(link for link in cached_links if str(link.get("local_port_id", "")) == port_id)
+            # Apply posted device override (VC member selection) without mutating the cached list.
+            link_data = {**link_data, "device_id": interface.get("device_id", link_data.get("device_id"))}
             return self.handle_cable_creation(link_data, interface)
         except StopIteration:
             return {"status": "invalid", "interface": port_id}
@@ -93,7 +110,6 @@ def verify_cable_creation_requirements(self, link_data):
         """Return True if all required NetBox IDs are present in link data."""
         required_fields = [
             "netbox_local_interface_id",
-            "netbox_remote_device_id",
             "netbox_remote_interface_id",
         ]
 
@@ -122,13 +138,22 @@ def handle_cable_creation(self, link_data, interface):
             return {"status": "missing_remote", "interface": display_name}
 
     def process_interface_sync(self, selected_interfaces, cached_links):
-        """Process cable sync for all selected interfaces and return results."""
+        """
+        Process cable sync for all selected interfaces and return results.
+
+        Each interface is processed in its own atomic block so individual
+        failures roll back only that cable without affecting others.
+        """
         results = {"valid": [], "invalid": [], "duplicate": [], "missing_remote": []}
 
-        with transaction.atomic():
-            for interface in selected_interfaces:
-                result = self.process_single_interface(interface, cached_links)
+        for interface in selected_interfaces:
+            try:
+                with transaction.atomic():
+                    result = self.process_single_interface(interface, cached_links)
                 results[result["status"]].append(result.get("interface", ""))
+            except Exception:
+                logger.exception("Failed to sync cable for port_id %s", interface.get("local_port_id", ""))
+                results["invalid"].append(interface.get("local_port_id", ""))
 
         return results
 
@@ -139,20 +164,23 @@ def post(self, request, pk):
             return error
 
         initial_device = get_object_or_404(Device, pk=pk)
+        server_key = request.POST.get("server_key") or self.librenms_api.server_key
+        self._post_server_key = server_key
+        redirect_url = (
+            f"{reverse('plugins:netbox_librenms_plugin:device_librenms_sync', args=[initial_device.pk])}?tab=cables"
+            + (f"&server_key={server_key}" if server_key else "")
+        )
+
         selected_interfaces = self.get_selected_interfaces(request, initial_device)
         cached_links = self.get_cached_links_data(request, initial_device)
 
         if not self.validate_prerequisites(cached_links, selected_interfaces):
-            return redirect(
-                f"{reverse('plugins:netbox_librenms_plugin:device_librenms_sync', args=[initial_device.pk])}?tab=cables"
-            )
+            return redirect(redirect_url)
 
         results = self.process_interface_sync(selected_interfaces, cached_links)
         self.display_sync_results(request, results)
 
-        return redirect(
-            f"{reverse('plugins:netbox_librenms_plugin:device_librenms_sync', args=[initial_device.pk])}?tab=cables"
-        )
+        return redirect(redirect_url)
 
     def display_sync_results(self, request, results):
         """Display flash messages summarizing the cable sync results."""
diff --git a/netbox_librenms_plugin/views/sync/device_fields.py b/netbox_librenms_plugin/views/sync/device_fields.py
index 4afc99ab62..a8e8d06af7 100644
--- a/netbox_librenms_plugin/views/sync/device_fields.py
+++ b/netbox_librenms_plugin/views/sync/device_fields.py
@@ -4,10 +4,17 @@
 from django.contrib import messages
 from django.core.exceptions import ValidationError
 from django.db import IntegrityError, transaction
+
+from django.http import HttpResponse
 from django.shortcuts import get_object_or_404, redirect
 from django.views import View
+from virtualization.models import VirtualMachine
 
-from netbox_librenms_plugin.utils import match_librenms_hardware_to_device_type
+from netbox_librenms_plugin.utils import (
+    find_by_librenms_id,
+    match_librenms_hardware_to_device_type,
+    migrate_legacy_librenms_id,
+)
 from netbox_librenms_plugin.views.mixins import LibreNMSAPIMixin, LibreNMSPermissionMixin, NetBoxObjectPermissionMixin
 
 logger = logging.getLogger(__name__)
@@ -148,7 +155,7 @@ def post(self, request, pk):
 
         match_result = match_librenms_hardware_to_device_type(hardware)
 
-        if not match_result["matched"]:
+        if not match_result or not match_result["matched"]:
             messages.error(
                 request,
                 f"No matching DeviceType found for hardware '{hardware}'",
@@ -432,3 +439,231 @@ def post(self, request, pk):
             messages.info(request, "No serial assignments were made")
 
         return redirect("plugins:netbox_librenms_plugin:device_librenms_sync", pk=pk)
+
+
+class RemoveServerMappingView(LibreNMSPermissionMixin, NetBoxObjectPermissionMixin, View):
+    """Remove a single server entry from the device's (or VM's) librenms_id custom field dict."""
+
+    required_object_permissions = {
+        "POST": [("change", Device), ("change", VirtualMachine)],
+    }
+
+    def _get_object(self, object_type, pk):
+        """Return the Device or VirtualMachine for the given pk."""
+        model = VirtualMachine if object_type == "vm" else Device
+        return get_object_or_404(model, pk=pk), model
+
+    def _sync_url_name(self, object_type):
+        if object_type == "vm":
+            return "plugins:netbox_librenms_plugin:vm_librenms_sync"
+        return "plugins:netbox_librenms_plugin:device_librenms_sync"
+
+    def _normalize_librenms_mapping(self, value):
+        if isinstance(value, bool):
+            return {}
+        if isinstance(value, int):
+            return {"default": value}
+        if isinstance(value, str) and value.isdigit():
+            return {"default": int(value)}
+        return value if isinstance(value, dict) else {}
+
+    def post(self, request, pk):
+        # Scope required permissions to the specific model being modified before checking.
+        object_type = request.POST.get("object_type", "device")
+        if object_type == "virtualmachine":
+            object_type = "vm"
+        if object_type not in ("device", "vm"):
+            return HttpResponse("Invalid object_type", status=400)
+        target_model = VirtualMachine if object_type == "vm" else Device
+        self.required_object_permissions = {"POST": [("change", target_model)]}
+
+        if error := self.require_all_permissions("POST"):
+            return error
+
+        obj, model = self._get_object(object_type, pk)
+        sync_url = self._sync_url_name(object_type)
+        server_key = request.POST.get("server_key", "").strip()
+
+        if not server_key:
+            messages.error(request, "No server_key provided.")
+            return redirect(sync_url, pk=pk)
+
+        cf_value = self._normalize_librenms_mapping(obj.custom_field_data.get("librenms_id"))
+        if not isinstance(cf_value, dict) or server_key not in cf_value:
+            messages.warning(request, f"No mapping found for server '{server_key}'.")
+            return redirect(sync_url, pk=pk)
+
+        # Refuse to remove mappings for servers that are still configured in the plugin.
+        # Only orphaned (unconfigured) mappings may be removed via this endpoint.
+        # Guard both multi-server mode (servers dict) and legacy single-server mode
+        # (top-level librenms_url in plugin config, which implicitly defines "default")
+        # but only when no servers section is configured (pure legacy mode).
+        from django.conf import settings as django_settings
+
+        plugins_cfg = django_settings.PLUGINS_CONFIG.get("netbox_librenms_plugin", {})
+        configured_servers = plugins_cfg.get("servers") or {}
+        if not isinstance(configured_servers, dict):
+            configured_servers = {}
+        legacy_url_configured = bool(plugins_cfg.get("librenms_url"))
+        if server_key in configured_servers or (
+            legacy_url_configured and not configured_servers and server_key == "default"
+        ):
+            messages.error(
+                request,
+                f"Cannot remove mapping for configured server '{server_key}'. "
+                "Remove the server from plugin configuration first, then retry.",
+            )
+            return redirect(sync_url, pk=pk)
+
+        with transaction.atomic():
+            try:
+                obj_locked = model.objects.select_for_update().get(pk=pk)
+            except model.DoesNotExist:
+                messages.error(request, f"{model.__name__} no longer exists.")
+                return redirect(sync_url, pk=pk)
+            cf = self._normalize_librenms_mapping(obj_locked.custom_field_data.get("librenms_id"))
+            # Re-check after acquiring lock; mirror the pre-transaction protection logic
+            _is_protected = server_key in configured_servers or (
+                legacy_url_configured and not configured_servers and server_key == "default"
+            )
+            if isinstance(cf, dict) and server_key in cf and not _is_protected:
+                del cf[server_key]
+                obj_locked.custom_field_data["librenms_id"] = cf if cf else None
+                try:
+                    obj_locked.full_clean()
+                    obj_locked.save()
+                except ValidationError as exc:
+                    transaction.set_rollback(True)
+                    error_msg = exc.message_dict if hasattr(exc, "message_dict") else str(exc)
+                    logger.exception(
+                        "Validation error removing LibreNMS mapping for server %r: %s", server_key, error_msg
+                    )
+                    messages.error(request, f"Validation error removing LibreNMS mapping: {error_msg}")
+                    return redirect(sync_url, pk=pk)
+                except Exception as exc:
+                    transaction.set_rollback(True)
+                    logger.exception("Unexpected error removing LibreNMS mapping for server %r", server_key)
+                    messages.error(request, f"Unexpected error removing LibreNMS mapping: {exc}")
+                    return redirect(sync_url, pk=pk)
+                messages.success(request, f"Removed LibreNMS mapping for server '{server_key}'.")
+            else:
+                messages.warning(request, f"Mapping for server '{server_key}' was already removed.")
+
+        return redirect(sync_url, pk=pk)
+
+
+class ConvertLegacyLibreNMSIdView(LibreNMSPermissionMixin, NetBoxObjectPermissionMixin, LibreNMSAPIMixin, View):
+    """
+    Convert a legacy bare-integer librenms_id to the server-scoped JSON dict format.
+
+    Only allowed when the NetBox serial matches the LibreNMS serial, so the
+    association can be verified before scoping the ID to the active server.
+    """
+
+    required_object_permissions = {
+        "POST": [("change", Device), ("change", VirtualMachine)],
+    }
+
+    def _get_model_and_object(self, object_type, pk):
+        model = VirtualMachine if object_type == "vm" else Device
+        return model, get_object_or_404(model, pk=pk)
+
+    def _sync_url(self, object_type, pk):
+        name = "vm_librenms_sync" if object_type == "vm" else "device_librenms_sync"
+        return redirect(f"plugins:netbox_librenms_plugin:{name}", pk=pk)
+
+    def post(self, request, pk):
+        object_type = request.POST.get("object_type", "device")
+        if object_type == "virtualmachine":
+            object_type = "vm"
+        if object_type not in ("device", "vm"):
+            return HttpResponse("Invalid object_type", status=400)
+
+        target_model = VirtualMachine if object_type == "vm" else Device
+        self.required_object_permissions = {"POST": [("change", target_model)]}
+        if error := self.require_all_permissions("POST"):
+            return error
+
+        model, obj = self._get_model_and_object(object_type, pk)
+        server_key = self.librenms_api.server_key
+
+        # Verify the device actually has a legacy bare-int librenms_id
+        cf_value = obj.custom_field_data.get("librenms_id")
+        if not isinstance(cf_value, (int, str)) or isinstance(cf_value, bool):
+            messages.warning(request, "librenms_id is already in the server-scoped JSON format.")
+            return self._sync_url(object_type, pk)
+        if isinstance(cf_value, str):
+            if not cf_value.isdigit():
+                messages.error(request, "librenms_id is not a valid integer; cannot convert.")
+                return self._sync_url(object_type, pk)
+
+        # Verify serial match before converting
+        librenms_id = int(cf_value) if isinstance(cf_value, str) else cf_value
+        success, device_info = self.librenms_api.get_device_info(librenms_id)
+        if not success or not device_info:
+            messages.error(request, "Could not retrieve device info from LibreNMS to verify serial.")
+            return self._sync_url(object_type, pk)
+
+        librenms_serial = (device_info.get("serial") or "").strip()
+        netbox_serial = (getattr(obj, "serial", None) or "").strip()
+        if not netbox_serial or not librenms_serial or netbox_serial != librenms_serial:
+            messages.error(
+                request,
+                "Serial number mismatch — cannot convert legacy ID without serial confirmation.",
+            )
+            return self._sync_url(object_type, pk)
+
+        with transaction.atomic():
+            try:
+                locked = model.objects.select_for_update().get(pk=pk)
+            except model.DoesNotExist:
+                messages.error(request, f"{model.__name__} no longer exists.")
+                return self._sync_url(object_type, pk)
+            # Re-check preconditions on the locked row (another admin may have
+            # changed cf_value or serial between the initial read and the lock).
+            locked_cf = locked.custom_field_data.get("librenms_id")
+            if not isinstance(locked_cf, (int, str)) or isinstance(locked_cf, bool):
+                messages.warning(request, "librenms_id is already in the server-scoped JSON format.")
+                return self._sync_url(object_type, pk)
+            locked_id = int(locked_cf) if isinstance(locked_cf, str) and locked_cf.isdigit() else locked_cf
+            if not isinstance(locked_id, int):
+                messages.error(request, "librenms_id changed before lock was acquired; aborting.")
+                return self._sync_url(object_type, pk)
+            locked_serial = (getattr(locked, "serial", None) or "").strip()
+            if locked_id != librenms_id or locked_serial != netbox_serial:
+                messages.error(request, "Device data changed before lock was acquired; aborting conversion.")
+                return self._sync_url(object_type, pk)
+            # Check that no other object already owns this ID (server-scoped or legacy)
+            match = find_by_librenms_id(model, librenms_id, server_key)
+            conflict = match is not None and match.pk != locked.pk
+            if conflict:
+                transaction.set_rollback(True)
+                messages.error(
+                    request,
+                    f"Another {model.__name__} already has librenms_id {librenms_id} "
+                    f"for server '{server_key}'; cannot convert.",
+                )
+                return self._sync_url(object_type, pk)
+            migrated = migrate_legacy_librenms_id(locked, server_key)
+            if not migrated:
+                messages.warning(request, "librenms_id is already in the server-scoped JSON format.")
+                return self._sync_url(object_type, pk)
+            try:
+                locked.full_clean()
+                locked.save()
+            except ValidationError as exc:
+                transaction.set_rollback(True)
+                error_msg = exc.message_dict if hasattr(exc, "message_dict") else str(exc)
+                messages.error(request, f"Failed to save converted librenms_id: {error_msg}")
+                return self._sync_url(object_type, pk)
+            except Exception as exc:
+                transaction.set_rollback(True)
+                logger.exception("Failed saving converted librenms_id for %s/%s", object_type, pk)
+                messages.error(request, f"Failed to save converted librenms_id: {exc}")
+                return self._sync_url(object_type, pk)
+
+        messages.success(
+            request,
+            f"Converted legacy librenms_id {librenms_id} → {{'{server_key}': {librenms_id}}}.",
+        )
+        return self._sync_url(object_type, pk)
diff --git a/netbox_librenms_plugin/views/sync/devices.py b/netbox_librenms_plugin/views/sync/devices.py
index da0f9af5b0..71add20d48 100644
--- a/netbox_librenms_plugin/views/sync/devices.py
+++ b/netbox_librenms_plugin/views/sync/devices.py
@@ -21,12 +21,19 @@ def get_form_class(self):
             return AddToLIbreSNMPV1V2
         return AddToLIbreSNMPV3
 
-    def get_object(self, object_id):
-        """Return the Device or VirtualMachine for the given ID."""
+    def get_object(self, object_id, object_type=None):
+        """
+        Return the Device or VirtualMachine for the given ID.
+
+        Uses object_type hint when provided to avoid PK collision ambiguity
+        (Device and VirtualMachine share independent PK sequences).
+        """
+        if object_type == "virtualmachine":
+            return get_object_or_404(VirtualMachine, pk=object_id)
         try:
             return Device.objects.get(pk=object_id)
         except Device.DoesNotExist:
-            return VirtualMachine.objects.get(pk=object_id)
+            return get_object_or_404(VirtualMachine, pk=object_id)
 
     def post(self, request, object_id):
         """Add a device to LibreNMS using the submitted SNMP form."""
@@ -34,7 +41,7 @@ def post(self, request, object_id):
         if error := self.require_write_permission():
             return error
 
-        self.object = self.get_object(object_id)
+        self.object = self.get_object(object_id, request.POST.get("object_type"))
         form_class = self.get_form_class()
 
         snmp_version = request.POST.get("v1v2-snmp_version") or request.POST.get("v3-snmp_version")
diff --git a/netbox_librenms_plugin/views/sync/interfaces.py b/netbox_librenms_plugin/views/sync/interfaces.py
index 29269742b3..3f0c93fa4c 100644
--- a/netbox_librenms_plugin/views/sync/interfaces.py
+++ b/netbox_librenms_plugin/views/sync/interfaces.py
@@ -9,7 +9,7 @@
 from virtualization.models import VirtualMachine, VMInterface
 
 from netbox_librenms_plugin.models import InterfaceTypeMapping
-from netbox_librenms_plugin.utils import convert_speed_to_kbps, get_interface_name_field
+from netbox_librenms_plugin.utils import convert_speed_to_kbps, get_interface_name_field, set_librenms_device_id
 from netbox_librenms_plugin.views.mixins import (
     CacheMixin,
     LibreNMSAPIMixin,
@@ -52,23 +52,27 @@ def post(self, request, object_type, object_id):
         obj = self.get_object(object_type, object_id)
         self.object = obj  # Store for use in sync methods
 
+        # Read server_key from POST so we use the exact server the user was viewing
+        server_key = request.POST.get("server_key") or self.librenms_api.server_key
+        self._post_server_key = server_key
+
         interface_name_field = get_interface_name_field(request)
         self.interface_name_field = interface_name_field
         selected_interfaces = self.get_selected_interfaces(request, interface_name_field)
         exclude_columns = request.POST.getlist("exclude_columns")
 
+        redirect_url = (
+            reverse(url_name, kwargs={"pk": object_id})
+            + f"?tab=interfaces&interface_name_field={interface_name_field}"
+            + (f"&server_key={server_key}" if server_key else "")
+        )
+
         if selected_interfaces is None:
-            return redirect(
-                reverse(url_name, kwargs={"pk": object_id})
-                + f"?tab=interfaces&interface_name_field={interface_name_field}"
-            )
+            return redirect(redirect_url)
 
-        ports_data = self.get_cached_ports_data(request, obj)
+        ports_data = self.get_cached_ports_data(request, obj, server_key)
         if ports_data is None:
-            return redirect(
-                reverse(url_name, kwargs={"pk": object_id})
-                + f"?tab=interfaces&interface_name_field={interface_name_field}"
-            )
+            return redirect(redirect_url)
 
         # Prepare VLAN lookup maps if VLAN sync is enabled
         vlan_groups = self.get_vlan_groups_for_device(obj)
@@ -78,9 +82,7 @@ def post(self, request, object_type, object_id):
         self.sync_selected_interfaces(obj, selected_interfaces, ports_data, exclude_columns, interface_name_field)
 
         messages.success(request, "Selected interfaces synced successfully.")
-        return redirect(
-            reverse(url_name, kwargs={"pk": object_id}) + f"?tab=interfaces&interface_name_field={interface_name_field}"
-        )
+        return redirect(redirect_url)
 
     def get_object(self, object_type, object_id):
         """Return the Device or VirtualMachine for the given type and ID."""
@@ -98,9 +100,11 @@ def get_selected_interfaces(self, request, interface_name_field):
             return None
         return selected_interfaces
 
-    def get_cached_ports_data(self, request, obj):
+    def get_cached_ports_data(self, request, obj, server_key=None):
         """Return cached LibreNMS port data for the given object."""
-        cached_data = cache.get(self.get_cache_key(obj, "ports"))
+        if server_key is None:
+            server_key = self.librenms_api.server_key
+        cached_data = cache.get(self.get_cache_key(obj, "ports", server_key))
         if not cached_data:
             messages.warning(
                 request,
@@ -232,8 +236,10 @@ def update_interface_attributes(
             else:
                 setattr(interface, netbox_key, librenms_interface.get(librenms_key))
 
-        if "librenms_id" in interface.cf:
-            interface.custom_field_data["librenms_id"] = librenms_interface.get("port_id")
+        port_id = librenms_interface.get("port_id")
+        if port_id is not None:
+            server_key = getattr(self, "_post_server_key", None) or self.librenms_api.server_key
+            set_librenms_device_id(interface, port_id, server_key)
 
         if "enabled" not in exclude_columns:
             admin_status = librenms_interface.get("ifAdminStatus")
diff --git a/netbox_librenms_plugin/views/sync/ip_addresses.py b/netbox_librenms_plugin/views/sync/ip_addresses.py
index 474a3a446c..82e3e2e85d 100644
--- a/netbox_librenms_plugin/views/sync/ip_addresses.py
+++ b/netbox_librenms_plugin/views/sync/ip_addresses.py
@@ -9,10 +9,15 @@
 from ipam.models import VRF, IPAddress
 from virtualization.models import VirtualMachine, VMInterface
 
-from netbox_librenms_plugin.views.mixins import CacheMixin, LibreNMSPermissionMixin, NetBoxObjectPermissionMixin
+from netbox_librenms_plugin.views.mixins import (
+    CacheMixin,
+    LibreNMSAPIMixin,
+    LibreNMSPermissionMixin,
+    NetBoxObjectPermissionMixin,
+)
 
 
-class SyncIPAddressesView(LibreNMSPermissionMixin, NetBoxObjectPermissionMixin, CacheMixin, View):
+class SyncIPAddressesView(LibreNMSPermissionMixin, NetBoxObjectPermissionMixin, LibreNMSAPIMixin, CacheMixin, View):
     """Synchronize IP addresses from LibreNMS cache into NetBox."""
 
     required_object_permissions = {
@@ -40,7 +45,8 @@ def get_vrf_selection(self, request, ip_address):
 
     def get_cached_ip_data(self, request, obj):
         """Return cached LibreNMS IP address data for the given object."""
-        cached_data = cache.get(self.get_cache_key(obj, "ip_addresses"))
+        server_key = getattr(self, "_post_server_key", None) or self.librenms_api.server_key
+        cached_data = cache.get(self.get_cache_key(obj, "ip_addresses", server_key))
         if not cached_data:
             return None
         return cached_data.get("ip_addresses", [])
@@ -59,7 +65,11 @@ def get_ip_tab_url(self, obj):
             url_name = "plugins:netbox_librenms_plugin:device_librenms_sync"
         else:
             url_name = "plugins:netbox_librenms_plugin:vm_librenms_sync"
-        return f"{reverse(url_name, args=[obj.pk])}?tab=ipaddresses"
+        server_key = getattr(self, "_post_server_key", None) or self.librenms_api.server_key
+        url = f"{reverse(url_name, args=[obj.pk])}?tab=ipaddresses"
+        if server_key:
+            url += f"&server_key={server_key}"
+        return url
 
     def post(self, request, object_type, pk):
         """Sync selected IP addresses from LibreNMS into NetBox."""
@@ -67,6 +77,9 @@ def post(self, request, object_type, pk):
         if error := self.require_all_permissions("POST"):
             return error
 
+        # Read server_key from POST so we use the exact server the user was viewing
+        self._post_server_key = request.POST.get("server_key") or self.librenms_api.server_key
+
         obj = self.get_object(object_type, pk)
 
         selected_ips = self.get_selected_ips(request)
diff --git a/netbox_librenms_plugin/views/sync/vlans.py b/netbox_librenms_plugin/views/sync/vlans.py
index c5fae91530..347a5deb14 100644
--- a/netbox_librenms_plugin/views/sync/vlans.py
+++ b/netbox_librenms_plugin/views/sync/vlans.py
@@ -8,10 +8,15 @@
 from django.views import View
 from ipam.models import VLAN, VLANGroup
 
-from netbox_librenms_plugin.views.mixins import CacheMixin, LibreNMSPermissionMixin, NetBoxObjectPermissionMixin
+from netbox_librenms_plugin.views.mixins import (
+    CacheMixin,
+    LibreNMSAPIMixin,
+    LibreNMSPermissionMixin,
+    NetBoxObjectPermissionMixin,
+)
 
 
-class SyncVLANsView(LibreNMSPermissionMixin, NetBoxObjectPermissionMixin, CacheMixin, View):
+class SyncVLANsView(LibreNMSPermissionMixin, NetBoxObjectPermissionMixin, LibreNMSAPIMixin, CacheMixin, View):
     """
     Handle POST requests to create/update VLANs in NetBox from LibreNMS data.
     """
@@ -36,6 +41,9 @@ def post(self, request, object_type: str, object_id: int):
         if error := self.require_all_permissions("POST"):
             return error
 
+        # Read server_key from POST so we use the exact server the user was viewing
+        self._post_server_key = request.POST.get("server_key") or self.librenms_api.server_key
+
         obj = self.get_object(object_type, object_id)
         action = request.POST.get("action", "")
 
@@ -58,7 +66,11 @@ def _redirect(self, object_type: str, object_id: int):
             if object_type == "device"
             else "plugins:netbox_librenms_plugin:vm_librenms_sync"
         )
-        return redirect(reverse(url_name, kwargs={"pk": object_id}) + "?tab=vlans")
+        server_key = getattr(self, "_post_server_key", None) or self.librenms_api.server_key
+        url = reverse(url_name, kwargs={"pk": object_id}) + "?tab=vlans"
+        if server_key:
+            url += f"&server_key={server_key}"
+        return redirect(url)
 
     def _handle_create_vlans(self, request, obj, object_type, object_id):
         """
@@ -73,7 +85,7 @@ def _handle_create_vlans(self, request, obj, object_type, object_id):
             return self._redirect(object_type, object_id)
 
         # Get cached VLAN data
-        cached_vlans = cache.get(self.get_cache_key(obj, "vlans"))
+        cached_vlans = cache.get(self.get_cache_key(obj, "vlans", self._post_server_key))
         if not cached_vlans:
             messages.error(request, "No cached VLAN data. Please refresh VLANs first.")
             return self._redirect(object_type, object_id)
diff --git a/pyproject.toml b/pyproject.toml
index 141a9f78f1..43f998dee1 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -46,6 +46,12 @@ python_classes = "Test*"
 python_functions = "test_*"
 addopts = "-v --tb=short"
 
+[tool.coverage.run]
+omit = [
+    "*/tests/*",
+    "*/test_*.py",
+]
+
 [tool.ruff]
 line-length = 120
 
diff --git a/uv.lock b/uv.lock
new file mode 100644
index 0000000000..32ce70698f
--- /dev/null
+++ b/uv.lock
@@ -0,0 +1,8 @@
+version = 1
+revision = 3
+requires-python = ">=3.12.0"
+
+[[package]]
+name = "netbox-librenms-plugin"
+version = "0.4.3"
+source = { editable = "." }

From 4b02a5c6ec3e1b763909e6edaafcbe231900b4f5 Mon Sep 17 00:00:00 2001
From: Marcin Zieba <marcinpsk@gmail.com>
Date: Thu, 12 Mar 2026 09:04:29 +0000
Subject: [PATCH 04/22] fix: address CR review findings from PR #41

- test_integration_sync: fix mock endpoint path for test_null_inventory_returns_false;
  get_device_inventory() calls /api/v0/inventory/{id}/all, not /api/v0/devices/{id}/inventory
- librenms_sync_view: skip serial gate for VMs when computing librenms_id_serial_confirmed;
  VirtualMachine has no serial field so the gate always blocked VM legacy-ID conversion
- device_fields: skip serial check for VMs in ConvertLegacyLibreNMSIdView; same root cause
- actions: expand VM action guard from migrate_librenms_id-only to also allow sync_name;
  hostname sync (sync_name) is valid for virtual machines
---
 netbox_librenms_plugin/tests/test_integration_sync.py   | 2 +-
 netbox_librenms_plugin/views/base/librenms_sync_view.py | 6 ++++--
 netbox_librenms_plugin/views/imports/actions.py         | 5 +++--
 netbox_librenms_plugin/views/sync/device_fields.py      | 4 +++-
 4 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/netbox_librenms_plugin/tests/test_integration_sync.py b/netbox_librenms_plugin/tests/test_integration_sync.py
index b7eb266868..fc7d244ca0 100644
--- a/netbox_librenms_plugin/tests/test_integration_sync.py
+++ b/netbox_librenms_plugin/tests/test_integration_sync.py
@@ -369,7 +369,7 @@ def test_500_returns_false(self, mock_server):
     def test_null_inventory_returns_false(self, mock_server):
         """{"status":"ok","inventory":null} must not raise, must return (False, ...)."""
         api = _make_api(mock_server.url)
-        mock_server.register("/api/v0/devices/1/inventory", {"status": "ok", "inventory": None})
+        mock_server.register("/api/v0/inventory/1/all", {"status": "ok", "inventory": None})
         success, data = api.get_device_inventory(1)
         assert success is False
 
diff --git a/netbox_librenms_plugin/views/base/librenms_sync_view.py b/netbox_librenms_plugin/views/base/librenms_sync_view.py
index ad94988903..258c8fa73c 100644
--- a/netbox_librenms_plugin/views/base/librenms_sync_view.py
+++ b/netbox_librenms_plugin/views/base/librenms_sync_view.py
@@ -112,10 +112,12 @@ def get_context_data(self, request, obj):
             isinstance(_raw_cf, str) and _raw_cf.isdigit()
         )
 
-        # Determine if serial match allows legacy ID conversion
+        # Determine if serial match allows legacy ID conversion.
+        # VMs have no serial field in NetBox; skip the gate so the Convert ID button is enabled.
         _librenms_serial = librenms_info["librenms_device_details"].get("librenms_device_serial", "-")
         _netbox_serial = getattr(_lookup_device, "serial", "") or ""
-        librenms_id_serial_confirmed = bool(
+        _lookup_is_vm = _lookup_device._meta.model_name == "virtualmachine" if _lookup_device else False
+        librenms_id_serial_confirmed = _lookup_is_vm or bool(
             _librenms_serial and _librenms_serial != "-" and _netbox_serial and _librenms_serial == _netbox_serial
         )
 
diff --git a/netbox_librenms_plugin/views/imports/actions.py b/netbox_librenms_plugin/views/imports/actions.py
index 3064cd1f95..e50534de0d 100644
--- a/netbox_librenms_plugin/views/imports/actions.py
+++ b/netbox_librenms_plugin/views/imports/actions.py
@@ -997,10 +997,11 @@ def post(self, request, device_id):
         if not action or not existing_device_id:
             return HttpResponse("Missing action or existing_device_id", status=400)
 
-        # VirtualMachine is supported for migrate_librenms_id only; all other actions
+        # VirtualMachine supports migrate_librenms_id and sync_name; all other actions
         # operate on Device-specific fields (serial, device_type) and remain Device-only.
+        _VM_SUPPORTED_ACTIONS = frozenset({"migrate_librenms_id", "sync_name"})
         if existing_device_type == "virtualmachine":
-            if action != "migrate_librenms_id":
+            if action not in _VM_SUPPORTED_ACTIONS:
                 return HttpResponse(
                     f"Action '{escape(action)}' is not supported for virtual machines",
                     status=400,
diff --git a/netbox_librenms_plugin/views/sync/device_fields.py b/netbox_librenms_plugin/views/sync/device_fields.py
index a8e8d06af7..5a2dd0f2fa 100644
--- a/netbox_librenms_plugin/views/sync/device_fields.py
+++ b/netbox_librenms_plugin/views/sync/device_fields.py
@@ -606,7 +606,9 @@ def post(self, request, pk):
 
         librenms_serial = (device_info.get("serial") or "").strip()
         netbox_serial = (getattr(obj, "serial", None) or "").strip()
-        if not netbox_serial or not librenms_serial or netbox_serial != librenms_serial:
+        # VMs have no serial field in NetBox; skip the serial gate for them.
+        is_vm = (object_type == "vm")
+        if not is_vm and (not netbox_serial or not librenms_serial or netbox_serial != librenms_serial):
             messages.error(
                 request,
                 "Serial number mismatch — cannot convert legacy ID without serial confirmation.",

From 761156c5ab2cb12defaf1446c051fc76bafc69ad Mon Sep 17 00:00:00 2001
From: Marcin Zieba <marcinpsk@gmail.com>
Date: Thu, 12 Mar 2026 09:27:59 +0000
Subject: [PATCH 05/22] fix: address remaining CR review findings from PR #41

- utils.py: treat device_id=0 as invalid (LibreNMS MySQL IDs start at 1);
  change "is not None" guard to truthy check in get_librenms_sync_device
- test_utils.py: replace wrong "0 is valid" assertion with correct two-member
  test confirming member with real ID is preferred over member with id=0
- librenms_api.py: remove redundant isinstance(result, dict) checks inside
  branch already guarded by the same isinstance check
- mock_librenms_server.py: register /all path in vc_inventory_callable so
  get_device_inventory() (/api/v0/inventory/{id}/all) hits the correct handler
- interfaces.py: resolve VC sync device for cache key in get_cached_ports_data;
  POST path now reads the same cache entry as the GET tab for VC members without
  their own server mapping
- librenms_sync.js: remove CSRF header from GET preview fetch (state-changing
  requests only); add pendingVlanVerifications counter to disable Save while
  async verifyVlanInGroup calls are in flight, preventing stale-state race
- docs/usage_tips/custom_field.md: clarify manual entry format shows JSON object
  e.g. {"production": 42}, not a bare integer
---
 docs/usage_tips/custom_field.md               |  6 +++-
 netbox_librenms_plugin/librenms_api.py        |  4 +--
 .../js/librenms_sync.js                       | 29 +++++++++++++++----
 .../tests/mock_librenms_server.py             |  1 +
 netbox_librenms_plugin/tests/test_utils.py    | 29 ++++++++++++-------
 netbox_librenms_plugin/utils.py               |  2 +-
 .../views/sync/interfaces.py                  | 17 +++++++++--
 7 files changed, 67 insertions(+), 21 deletions(-)

diff --git a/docs/usage_tips/custom_field.md b/docs/usage_tips/custom_field.md
index 0127d19efc..5891569c3e 100644
--- a/docs/usage_tips/custom_field.md
+++ b/docs/usage_tips/custom_field.md
@@ -69,7 +69,11 @@ You can manually assign a value to the `librenms_id` custom field for a device u
 2. **Set the LibreNMS ID:**
 
     - Scroll to the **Custom Fields** section.
-    - Enter the LibreNMS device ID in the `librenms_id` field.
+    - Enter the `librenms_id` value as a JSON object with your server key(s):
+      ```json
+      {"production": 42}
+      ```
+      For multiple servers: `{"production": 42, "staging": 17}`
 
 3. **Save Changes:**
 
diff --git a/netbox_librenms_plugin/librenms_api.py b/netbox_librenms_plugin/librenms_api.py
index 100b81a349..adb483d2aa 100644
--- a/netbox_librenms_plugin/librenms_api.py
+++ b/netbox_librenms_plugin/librenms_api.py
@@ -942,9 +942,9 @@ def get_device_vlans(self, device_id: int) -> tuple[bool, list | str]:
 
             result = response.json()
             if isinstance(result, dict) and result.get("status") == "ok":
-                all_vlans = result.get("vlans") if isinstance(result, dict) else None
+                all_vlans = result.get("vlans")
                 if not isinstance(all_vlans, list):
-                    msg = result.get("message") if isinstance(result, dict) else None
+                    msg = result.get("message")
                     return False, msg or "Unexpected response format: missing 'vlans' list"
                 # Filter VLANs by device_id since resources endpoint returns all VLANs
                 device_vlans = [
diff --git a/netbox_librenms_plugin/static/netbox_librenms_plugin/js/librenms_sync.js b/netbox_librenms_plugin/static/netbox_librenms_plugin/js/librenms_sync.js
index 5b020bb366..3d5f54c026 100644
--- a/netbox_librenms_plugin/static/netbox_librenms_plugin/js/librenms_sync.js
+++ b/netbox_librenms_plugin/static/netbox_librenms_plugin/js/librenms_sync.js
@@ -441,8 +441,22 @@ function updateHiddenVlanGroupInput(safeName, vid, groupId) {
  * @param {string} vlanType - "U" for untagged, "T" for tagged
  * @param {string} groupId - Selected group ID
  */
+let pendingVlanVerifications = 0;
+
+function _vlanVerifyStart(saveBtn) {
+    pendingVlanVerifications++;
+    if (saveBtn) saveBtn.disabled = true;
+}
+
+function _vlanVerifyEnd(saveBtn) {
+    pendingVlanVerifications = Math.max(0, pendingVlanVerifications - 1);
+    if (saveBtn && pendingVlanVerifications === 0) saveBtn.disabled = false;
+}
+
 function verifyVlanInGroup(select, deviceId, vid, vlanType, groupId) {
-    if (!deviceId) return;
+
+    const saveBtn = document.getElementById('saveVlanGroups');
+    _vlanVerifyStart(saveBtn);
 
     fetch('/plugins/librenms_plugin/verify-vlan-group/', {
         method: 'POST',
@@ -458,7 +472,12 @@ function verifyVlanInGroup(select, deviceId, vid, vlanType, groupId) {
             vlan_type: vlanType
         })
     })
-        .then(response => response.json())
+        .then(response => {
+            if (!response.ok) {
+                return response.text().then(t => { throw new Error(t || `HTTP ${response.status}`); });
+            }
+            return response.json();
+        })
         .then(data => {
             if (data.status === 'success') {
                 const newCss = data.css_class || 'text-danger';
@@ -505,8 +524,9 @@ function verifyVlanInGroup(select, deviceId, vid, vlanType, groupId) {
                 }
             }
         })
-        .catch(error => {
-            console.error('VLAN verification error:', error);
+        .finally(() => {
+            const saveBtn = document.getElementById('saveVlanGroups');
+            _vlanVerifyEnd(saveBtn);
         });
 }
 
@@ -1549,7 +1569,6 @@ function initializeModuleReplaceButtons() {
             // Fetch preview content and inject into modal body
             fetch(`${previewUrl}?${params.toString()}`, {
                 signal,
-                headers: { 'X-CSRFToken': document.querySelector('[name=csrfmiddlewaretoken]').value },
             })
                 .then(response => {
                     if (!response.ok) return response.text().then(t => { throw new Error(t); });
diff --git a/netbox_librenms_plugin/tests/mock_librenms_server.py b/netbox_librenms_plugin/tests/mock_librenms_server.py
index 588515dfd9..060ba62006 100644
--- a/netbox_librenms_plugin/tests/mock_librenms_server.py
+++ b/netbox_librenms_plugin/tests/mock_librenms_server.py
@@ -238,6 +238,7 @@ def _handler(method, path, query, headers, body):
             return 200, {"status": "ok", "inventory": all_items}
 
         self.routes[f"/api/v0/inventory/{device_id}"] = _handler
+        self.routes[f"/api/v0/inventory/{device_id}/all"] = _handler
 
 
 @contextmanager
diff --git a/netbox_librenms_plugin/tests/test_utils.py b/netbox_librenms_plugin/tests/test_utils.py
index e78144e149..caae8f6886 100644
--- a/netbox_librenms_plugin/tests/test_utils.py
+++ b/netbox_librenms_plugin/tests/test_utils.py
@@ -416,26 +416,35 @@ def test_get_librenms_sync_device_dict_for_different_server_falls_through(self):
 
         assert result == member_a
 
-    def test_zero_id_is_still_valid(self):
-        """A zero-valued LibreNMS ID must not be treated as missing (is not None guard)."""
+    def test_zero_id_is_not_a_valid_librenms_id(self):
+        """LibreNMS uses MySQL auto-increment IDs starting at 1; device_id=0 cannot exist.
+        A member whose resolved ID is 0 must be skipped so a real ID is preferred."""
         from netbox_librenms_plugin.utils import get_librenms_sync_device
 
         device = MagicMock()
         vc = MagicMock()
         device.virtual_chassis = vc
+        vc.master = None
 
-        member = MagicMock()
-        member.cf = {"librenms_id": 0}  # zero is a valid LibreNMS ID
-        member.custom_field_data = {"librenms_id": 0}
+        member_zero = MagicMock()
+        member_zero.primary_ip = None
+        member_real = MagicMock()
+        member_real.primary_ip = None
 
-        # Simulate get_librenms_device_id returning 0 (not None) for member
+        def _id_side_effect(obj, server_key, **kwargs):
+            if obj is member_zero:
+                return 0
+            if obj is member_real:
+                return 5
+            return None
+
+        # member_zero comes first but has id=0; member_real has id=5 — real ID wins
         with patch("netbox_librenms_plugin.utils.get_librenms_device_id") as mock_get_id:
-            mock_get_id.side_effect = lambda obj, server_key, **kwargs: 0 if obj is member else None
-            vc.members.all.return_value = [member]
+            mock_get_id.side_effect = _id_side_effect
+            vc.members.all.return_value = [member_zero, member_real]
             result = get_librenms_sync_device(device, server_key="default")
 
-        # 0 is a valid ID — should not be treated as "no ID"
-        assert result is member
+        assert result is member_real
 
 
 # =============================================================================
diff --git a/netbox_librenms_plugin/utils.py b/netbox_librenms_plugin/utils.py
index c28f93e7c8..869c6357bc 100644
--- a/netbox_librenms_plugin/utils.py
+++ b/netbox_librenms_plugin/utils.py
@@ -121,7 +121,7 @@ def get_librenms_sync_device(device: Device, server_key: str = None) -> Optional
         # (includes bare-int legacy IDs that are a universal fallback).
         for member in all_members:
             result = get_librenms_device_id(member, server_key, auto_save=False)
-            if result is not None:
+            if result:
                 return member
     else:
         # server_key is None: match any member that has any librenms_id set (any server).
diff --git a/netbox_librenms_plugin/views/sync/interfaces.py b/netbox_librenms_plugin/views/sync/interfaces.py
index 3f0c93fa4c..3f89653ada 100644
--- a/netbox_librenms_plugin/views/sync/interfaces.py
+++ b/netbox_librenms_plugin/views/sync/interfaces.py
@@ -9,7 +9,13 @@
 from virtualization.models import VirtualMachine, VMInterface
 
 from netbox_librenms_plugin.models import InterfaceTypeMapping
-from netbox_librenms_plugin.utils import convert_speed_to_kbps, get_interface_name_field, set_librenms_device_id
+from netbox_librenms_plugin.utils import (
+    convert_speed_to_kbps,
+    get_interface_name_field,
+    get_librenms_device_id,
+    get_librenms_sync_device,
+    set_librenms_device_id,
+)
 from netbox_librenms_plugin.views.mixins import (
     CacheMixin,
     LibreNMSAPIMixin,
@@ -104,7 +110,14 @@ def get_cached_ports_data(self, request, obj, server_key=None):
         """Return cached LibreNMS port data for the given object."""
         if server_key is None:
             server_key = self.librenms_api.server_key
-        cached_data = cache.get(self.get_cache_key(obj, "ports", server_key))
+        # On VC member pages the GET tab writes ports under the resolved sync device's
+        # cache key. Resolve the same device here so the POST path reads the same entry.
+        cache_obj = obj
+        if isinstance(obj, Device) and get_librenms_device_id(obj, server_key, auto_save=False) is None:
+            sync_device = get_librenms_sync_device(obj, server_key=server_key)
+            if sync_device is not None:
+                cache_obj = sync_device
+        cached_data = cache.get(self.get_cache_key(cache_obj, "ports", server_key))
         if not cached_data:
             messages.warning(
                 request,

From cbe49db5505188556fe6ea8b62450398f4de26fb Mon Sep 17 00:00:00 2001
From: Marcin Zieba <marcinpsk@gmail.com>
Date: Thu, 12 Mar 2026 10:14:18 +0000
Subject: [PATCH 06/22] fix: CR review follow-up fixes for PR #41

- test_integration_sync.py: add missing assert data is None for empty devices list test
- librenms_api.py: remove redundant isinstance(data, dict) checks inside isinstance guard
- .devcontainer/README.md: fix anchor to match emoji-prefixed header slug
- docs/development/testing.md: update integration test example to include VC suite (test_integration_*.py)
---
 .devcontainer/README.md                               | 2 +-
 docs/development/testing.md                           | 2 +-
 netbox_librenms_plugin/librenms_api.py                | 4 ++--
 netbox_librenms_plugin/tests/test_integration_sync.py | 1 +
 4 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/.devcontainer/README.md b/.devcontainer/README.md
index 7dc3ef967a..e33c3c525c 100644
--- a/.devcontainer/README.md
+++ b/.devcontainer/README.md
@@ -46,7 +46,7 @@ If you need to test with a LibreNMS instance on a private network (local lab, co
 2. Open in VS Code and choose "Reopen in Container" (or Ctrl+Shift+P → Dev Containers: Reopen in Container)
 3. Wait for setup (~5min on first run or when new NetBox image is used). The container will install the plugin and prep NetBox
 4. Set up GitHub access: `gh auth login` (for pushing/pulling code changes)
-5. Create your plugin config — see [LibreNMS Server configuration](#librenms-server-configuration):
+5. Create your plugin config — see [LibreNMS Server configuration](#📡-librenms-server-configuration):
    - `cp .devcontainer/config/plugin-config.py.example .devcontainer/config/plugin-config.py`
    - Edit it with your server details (tokens/URLs)
 6. Start NetBox with `netbox-run` (or `netbox-run-bg` in background) (see [Commands](#-commands-aliases))
diff --git a/docs/development/testing.md b/docs/development/testing.md
index 58f041c09e..42565cb76e 100644
--- a/docs/development/testing.md
+++ b/docs/development/testing.md
@@ -91,7 +91,7 @@ pytest netbox_librenms_plugin/tests/test_librenms_id.py -v
 pytest netbox_librenms_plugin/tests/test_sync_devices.py netbox_librenms_plugin/tests/test_sync_interfaces.py netbox_librenms_plugin/tests/test_sync_modules.py -v
 
 # Integration tests (API client against mock HTTP server)
-pytest netbox_librenms_plugin/tests/test_integration_sync.py -v
+pytest netbox_librenms_plugin/tests/test_integration_*.py -v
 
 # Sync view mismatch detection and permission enforcement
 pytest netbox_librenms_plugin/tests/test_sync_view_mismatch.py netbox_librenms_plugin/tests/test_permissions.py -v
diff --git a/netbox_librenms_plugin/librenms_api.py b/netbox_librenms_plugin/librenms_api.py
index adb483d2aa..0cceab18b7 100644
--- a/netbox_librenms_plugin/librenms_api.py
+++ b/netbox_librenms_plugin/librenms_api.py
@@ -789,9 +789,9 @@ def get_inventory_filtered(self, device_id, ent_physical_class=None, ent_physica
 
             data = response.json()
             if isinstance(data, dict) and data.get("status") == "ok":
-                inventory = data.get("inventory") if isinstance(data, dict) else None
+                inventory = data.get("inventory")
                 if not isinstance(inventory, list):
-                    msg = data.get("message") if isinstance(data, dict) else None
+                    msg = data.get("message")
                     return False, msg or "Unexpected response format: missing 'inventory' list"
                 logger.debug(f"API returned {len(inventory)} items")
 
diff --git a/netbox_librenms_plugin/tests/test_integration_sync.py b/netbox_librenms_plugin/tests/test_integration_sync.py
index fc7d244ca0..ed5fa8c993 100644
--- a/netbox_librenms_plugin/tests/test_integration_sync.py
+++ b/netbox_librenms_plugin/tests/test_integration_sync.py
@@ -387,6 +387,7 @@ def test_empty_devices_list_get_device_info(self, mock_server):
         mock_server.register("/api/v0/devices/42", {"devices": []})
         success, data = api.get_device_info(42)
         assert success is False
+        assert data is None
 
     def test_404_get_device_info(self, mock_server):
         """404 on device endpoint must return (False, None)."""

From d94eaafcea822374de49126be1e26f0873c76ecc Mon Sep 17 00:00:00 2001
From: Marcin Zieba <marcinpsk@gmail.com>
Date: Thu, 12 Mar 2026 10:37:03 +0000
Subject: [PATCH 07/22] fix: add sync_platform to VM supported actions, lint
 cleanup

- actions.py: add sync_platform to _VM_SUPPORTED_ACTIONS; both Device and
  VirtualMachine have a platform FK, so sync_platform is valid for VMs
- ruff format: remove redundant parens in device_fields.py (is_vm = object_type == "vm")
---
 netbox_librenms_plugin/views/imports/actions.py    | 6 +++---
 netbox_librenms_plugin/views/sync/device_fields.py | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/netbox_librenms_plugin/views/imports/actions.py b/netbox_librenms_plugin/views/imports/actions.py
index e50534de0d..ff199246cc 100644
--- a/netbox_librenms_plugin/views/imports/actions.py
+++ b/netbox_librenms_plugin/views/imports/actions.py
@@ -997,9 +997,9 @@ def post(self, request, device_id):
         if not action or not existing_device_id:
             return HttpResponse("Missing action or existing_device_id", status=400)
 
-        # VirtualMachine supports migrate_librenms_id and sync_name; all other actions
-        # operate on Device-specific fields (serial, device_type) and remain Device-only.
-        _VM_SUPPORTED_ACTIONS = frozenset({"migrate_librenms_id", "sync_name"})
+        # VirtualMachine supports migrate_librenms_id, sync_name, and sync_platform; all
+        # other actions operate on Device-specific fields (serial, device_type) and remain Device-only.
+        _VM_SUPPORTED_ACTIONS = frozenset({"migrate_librenms_id", "sync_name", "sync_platform"})
         if existing_device_type == "virtualmachine":
             if action not in _VM_SUPPORTED_ACTIONS:
                 return HttpResponse(
diff --git a/netbox_librenms_plugin/views/sync/device_fields.py b/netbox_librenms_plugin/views/sync/device_fields.py
index 5a2dd0f2fa..c6227b8101 100644
--- a/netbox_librenms_plugin/views/sync/device_fields.py
+++ b/netbox_librenms_plugin/views/sync/device_fields.py
@@ -607,7 +607,7 @@ def post(self, request, pk):
         librenms_serial = (device_info.get("serial") or "").strip()
         netbox_serial = (getattr(obj, "serial", None) or "").strip()
         # VMs have no serial field in NetBox; skip the serial gate for them.
-        is_vm = (object_type == "vm")
+        is_vm = object_type == "vm"
         if not is_vm and (not netbox_serial or not librenms_serial or netbox_serial != librenms_serial):
             messages.error(
                 request,

From 759c6cc1b8be387e5aad80672bf3f153065a5a01 Mon Sep 17 00:00:00 2001
From: Marcin Zieba <marcinpsk@gmail.com>
Date: Thu, 12 Mar 2026 10:51:19 +0000
Subject: [PATCH 08/22] revert: restore .devcontainer/README.md to main state
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Out of scope for this PR — devcontainer docs changes should go through
a dedicated maintenance PR, not bundled with feature/fix branches.
---
 .devcontainer/README.md | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/.devcontainer/README.md b/.devcontainer/README.md
index e33c3c525c..7024351758 100644
--- a/.devcontainer/README.md
+++ b/.devcontainer/README.md
@@ -44,20 +44,20 @@ If you need to test with a LibreNMS instance on a private network (local lab, co
 
 1. Fork and Clone: fork the plugin repo in Github and clone locally
 2. Open in VS Code and choose "Reopen in Container" (or Ctrl+Shift+P → Dev Containers: Reopen in Container)
-3. Wait for setup (~5min on first run or when new NetBox image is used). The container will install the plugin and prep NetBox
-4. Set up GitHub access: `gh auth login` (for pushing/pulling code changes)
-5. Create your plugin config — see [LibreNMS Server configuration](#📡-librenms-server-configuration):
+2. Wait for setup (~5min on first run or when new NetBox image is used). The container will install the plugin and prep NetBox
+3. Set up GitHub access: `gh auth login` (for pushing/pulling code changes)
+4. Create your plugin config — see [Plugin configuration](#plugin-configuration):
    - `cp .devcontainer/config/plugin-config.py.example .devcontainer/config/plugin-config.py`
    - Edit it with your server details (tokens/URLs)
-6. Start NetBox with `netbox-run` (or `netbox-run-bg` in background) (see [Commands](#-commands-aliases))
-7. Access NetBox at http://localhost:8000
+5. Start NetBox with `netbox-run` (or `netbox-run-bg` in background) (see [Commands](#-commands-aliases))
+6. Access NetBox at http://localhost:8000
    - Username: `admin`
    - Password: `admin`
 
 ### 🔄 Code changes and Committing
 8. Edit code in the repo root.  Check out [contributing docs](../docs/contributing.md)
 9. Use `netbox-logs` to follow log output on screen
-10. Commit changes and contribute as normal by submitting a PR on GitHub.
+6. Commit changes and contribute as normal by submitting a PR on GitHub.
 
 ### Quick Tips
 - **Auto-reload**: Works for most code changes when `DEBUG=True`
@@ -98,6 +98,8 @@ Below are the dev container defaults. The field name to change these defaults is
 - Plugin loader: enabled; reads `.devcontainer/config/plugin-config.py` if present
 - If `plugin-config.py` is missing: plugin is enabled with empty config (features won’t work until configured)
 
+
+
 ## 🔧 Configuration
 
 ### NetBox Version and Environment (use .devcontainer/.env)
@@ -241,7 +243,7 @@ After any `.env` change, rebuild the dev container to apply environment updates.
 
 ### Additional packages (including other netbox plugins)
 - Create `.devcontainer/extra-requirements.txt` for extra Python packages. Example: `.devcontainer/extra-requirements.txt.example`.
-   - After changes: run `plugin-install` to install packages, then `netbox-restart` (see [Commands](#-commands-aliases))
+   - After changes: run `plugins-install` to install packages, then `netbox-restart` (see [Commands](#-commands-aliases))
 
 ## 🔧 Git Setup
 
@@ -259,7 +261,7 @@ The dev container includes Git and GitHub CLI pre-installed. You'll need to conf
 git remote -v
 
 # If it shows git@github.com:..., convert to HTTPS
-git remote set-url origin https://github.com/<owner>/netbox-librenms-plugin.git
+git remote set-url origin https://github.com/bonzo81/netbox-librenms-plugin.git
 ```
 
 ### Recommended: GitHub CLI (Easiest)
@@ -347,14 +349,13 @@ fatal: Could not read from remote repository.
 1. **Check remote URL** - should use HTTPS, not SSH:
    ```bash
    git remote -v
-   # Should show: https://github.com/<owner>/netbox-librenms-plugin.git
-   # NOT: git@github.com:<owner>/netbox-librenms-plugin.git
+   # Should show: https://github.com/bonzo81/netbox-librenms-plugin.git
+   # NOT: git@github.com:bonzo81/netbox-librenms-plugin.git
    ```
 
 2. **Fix SSH remote URL**:
-
    ```bash
-   git remote set-url origin https://github.com/<owner>/netbox-librenms-plugin.git
+   git remote set-url origin https://github.com/bonzo81/netbox-librenms-plugin.git
    ```
 
 3. **Authenticate with GitHub CLI**:

From 302b739c9d64f1bbdf74ad94e713761892acd404 Mon Sep 17 00:00:00 2001
From: Marcin Zieba <marcinpsk@gmail.com>
Date: Thu, 12 Mar 2026 14:15:10 +0100
Subject: [PATCH 09/22] chore: restore devcontainer README; remove PR template
 not in develop

---
 .devcontainer/README.md          |  2 --
 .github/pull_request_template.md | 49 --------------------------------
 2 files changed, 51 deletions(-)
 delete mode 100644 .github/pull_request_template.md

diff --git a/.devcontainer/README.md b/.devcontainer/README.md
index 7024351758..3560a93af3 100644
--- a/.devcontainer/README.md
+++ b/.devcontainer/README.md
@@ -98,8 +98,6 @@ Below are the dev container defaults. The field name to change these defaults is
 - Plugin loader: enabled; reads `.devcontainer/config/plugin-config.py` if present
 - If `plugin-config.py` is missing: plugin is enabled with empty config (features won’t work until configured)
 
-
-
 ## 🔧 Configuration
 
 ### NetBox Version and Environment (use .devcontainer/.env)
diff --git a/.github/pull_request_template.md b/.github/pull_request_template.md
deleted file mode 100644
index 99ff02374f..0000000000
--- a/.github/pull_request_template.md
+++ /dev/null
@@ -1,49 +0,0 @@
-## Summary
-Briefly describe what this PR does in plain English, and provide as much of the following information as possible.
-
-## Motivation / Problem
-What issue does this solve?
-- Bug
-- Feature
-- Refactor
-- Maintenance / cleanup
-
-Link any related issues if applicable.
-
-## Scope of Change
-Delete items that don’t apply:
-
-- Sync/Import logic
-- NetBox models / ORM
-- LibreNMS API interaction
-- Config / settings
-- Web UI / templates
-- Database migrations
-- Tests
-- Docs only
-- Other: <describe>
-
-## How Was This Tested?
-Delete items that don’t apply and describe briefly.
-
-- Unit tests: <yes/no + what>
-- Manual testing: <yes/no + what>
-- Not tested: <explain why>
-
-### Manual Test Steps (if applicable)
-1.
-2.
-3.
-
-## Risk Assessment
-- Does this change affect existing users?
-- Could this cause unintended imports / updates?
-
-Explain briefly.
-
-## Backwards Compatibility
-- No breaking changes
-- Breaking change (explain and document)
-
-## Other Notes
-Anything the maintainer(s) should pay particular attention to?

From e483dce9b444a403e452616f836adcf68ef50179 Mon Sep 17 00:00:00 2001
From: Marcin Zieba <marcinpsk@gmail.com>
Date: Thu, 12 Mar 2026 14:29:11 +0100
Subject: [PATCH 10/22] fix(actions): skip device_type check for VMs; reject
 legacy bare-int librenms_id before link/update

_build_sync_info: the device_type_synced block ran for VirtualMachine
objects (which have no device_type attribute), causing device_type_synced
to flip False whenever LibreNMS reported hardware. Wrap the whole block
in an isinstance(existing_device, VirtualMachine) guard.

link/update/update_serial: set_librenms_device_id silently skips writes
when the stored librenms_id is a legacy bare-int/string, leaving the
device partially updated with no error surfaced to the user. Add a
pre-flight check inside the transaction that returns HTTP 409 with a
migration hint before any field mutations occur.
---
 .../views/imports/actions.py                  | 43 ++++++++++++++-----
 1 file changed, 32 insertions(+), 11 deletions(-)

diff --git a/netbox_librenms_plugin/views/imports/actions.py b/netbox_librenms_plugin/views/imports/actions.py
index ff199246cc..114f0b7ac9 100644
--- a/netbox_librenms_plugin/views/imports/actions.py
+++ b/netbox_librenms_plugin/views/imports/actions.py
@@ -865,19 +865,22 @@ def _build_sync_info(libre_device, existing_device):
         # Device type comparison (VMs don't have device_type)
         device_type_synced = True
         librenms_device_type = None
-        netbox_device_type = getattr(existing_device, "device_type", None)
-        if librenms_hardware and librenms_hardware != "-":
-            from netbox_librenms_plugin.utils import match_librenms_hardware_to_device_type
+        from virtualization.models import VirtualMachine
+
+        if not isinstance(existing_device, VirtualMachine):
+            netbox_device_type = getattr(existing_device, "device_type", None)
+            if librenms_hardware and librenms_hardware != "-":
+                from netbox_librenms_plugin.utils import match_librenms_hardware_to_device_type
 
-            hw_match = match_librenms_hardware_to_device_type(librenms_hardware)
-            if hw_match is None:
-                device_type_synced = False
-            elif hw_match.get("matched"):
-                librenms_device_type = hw_match["device_type"]
-                if not netbox_device_type or netbox_device_type.pk != librenms_device_type.pk:
+                hw_match = match_librenms_hardware_to_device_type(librenms_hardware)
+                if hw_match is None:
+                    device_type_synced = False
+                elif hw_match.get("matched"):
+                    librenms_device_type = hw_match["device_type"]
+                    if not netbox_device_type or netbox_device_type.pk != librenms_device_type.pk:
+                        device_type_synced = False
+                else:
                     device_type_synced = False
-            else:
-                device_type_synced = False
 
         all_synced = serial_synced and platform_synced and device_type_synced
 
@@ -1088,6 +1091,24 @@ def post(self, request, device_id):
                         status=409,
                     )
 
+                # Reject legacy bare-int/string librenms_id: set_librenms_device_id
+                # silently skips writes for legacy formats, leaving the device partially
+                # updated. User must run "Convert mapping" migration first.
+                stored_id = existing_device.custom_field_data.get("librenms_id")
+                _is_legacy = isinstance(stored_id, int) and not isinstance(stored_id, bool)
+                if not _is_legacy and isinstance(stored_id, str):
+                    try:
+                        int(stored_id)
+                        _is_legacy = True
+                    except (ValueError, TypeError):
+                        pass
+                if _is_legacy:
+                    return HttpResponse(
+                        "Device has a legacy bare-integer librenms_id; use 'Convert mapping' "
+                        "to migrate to the multi-server format before linking.",
+                        status=409,
+                    )
+
                 if action == "link":
                     # Link to LibreNMS and update name from LibreNMS data
                     hostname = _get_hostname_for_action(request, validation, libre_device)

From 3f32a46e1e99d60f09a048da74f17bbdfd8be9c6 Mon Sep 17 00:00:00 2001
From: Marcin Zieba <marcinpsk@gmail.com>
Date: Thu, 12 Mar 2026 15:39:14 +0100
Subject: [PATCH 11/22] fix(security): URL-encode server_key in redirects;
 reject librenms_id <= 0; add catch to verifyVlanInGroup

---
 .../static/netbox_librenms_plugin/js/librenms_sync.js         | 3 +++
 netbox_librenms_plugin/views/imports/actions.py               | 2 ++
 netbox_librenms_plugin/views/sync/cables.py                   | 3 ++-
 netbox_librenms_plugin/views/sync/interfaces.py               | 4 +++-
 netbox_librenms_plugin/views/sync/ip_addresses.py             | 4 +++-
 netbox_librenms_plugin/views/sync/vlans.py                    | 4 +++-
 6 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/netbox_librenms_plugin/static/netbox_librenms_plugin/js/librenms_sync.js b/netbox_librenms_plugin/static/netbox_librenms_plugin/js/librenms_sync.js
index 3d5f54c026..c2067eb166 100644
--- a/netbox_librenms_plugin/static/netbox_librenms_plugin/js/librenms_sync.js
+++ b/netbox_librenms_plugin/static/netbox_librenms_plugin/js/librenms_sync.js
@@ -524,6 +524,9 @@ function verifyVlanInGroup(select, deviceId, vid, vlanType, groupId) {
                 }
             }
         })
+        .catch(err => {
+            console.error('VLAN group verify failed:', err);
+        })
         .finally(() => {
             const saveBtn = document.getElementById('saveVlanGroups');
             _vlanVerifyEnd(saveBtn);
diff --git a/netbox_librenms_plugin/views/imports/actions.py b/netbox_librenms_plugin/views/imports/actions.py
index 114f0b7ac9..078db675ff 100644
--- a/netbox_librenms_plugin/views/imports/actions.py
+++ b/netbox_librenms_plugin/views/imports/actions.py
@@ -1058,6 +1058,8 @@ def post(self, request, device_id):
             librenms_id = int(librenms_id)
         except (TypeError, ValueError):
             return HttpResponse("Invalid or missing LibreNMS device_id in payload", status=400)
+        if librenms_id <= 0:
+            return HttpResponse("Invalid or missing LibreNMS device_id in payload", status=400)
 
         # Wrap the LibreNMS-ID collision check and subsequent write in a single
         # transaction so the read-then-write is atomic for link/update/update_serial.
diff --git a/netbox_librenms_plugin/views/sync/cables.py b/netbox_librenms_plugin/views/sync/cables.py
index 473d34777f..4404651d6a 100644
--- a/netbox_librenms_plugin/views/sync/cables.py
+++ b/netbox_librenms_plugin/views/sync/cables.py
@@ -1,4 +1,5 @@
 import logging
+from urllib.parse import quote_plus
 
 from dcim.models import Cable, Device, Interface
 from django.contrib import messages
@@ -168,7 +169,7 @@ def post(self, request, pk):
         self._post_server_key = server_key
         redirect_url = (
             f"{reverse('plugins:netbox_librenms_plugin:device_librenms_sync', args=[initial_device.pk])}?tab=cables"
-            + (f"&server_key={server_key}" if server_key else "")
+            + (f"&server_key={quote_plus(server_key)}" if server_key else "")
         )
 
         selected_interfaces = self.get_selected_interfaces(request, initial_device)
diff --git a/netbox_librenms_plugin/views/sync/interfaces.py b/netbox_librenms_plugin/views/sync/interfaces.py
index 3f89653ada..f3fe25b1ba 100644
--- a/netbox_librenms_plugin/views/sync/interfaces.py
+++ b/netbox_librenms_plugin/views/sync/interfaces.py
@@ -1,3 +1,5 @@
+from urllib.parse import quote_plus
+
 from dcim.models import Device, Interface, MACAddress
 from django.contrib import messages
 from django.core.cache import cache
@@ -70,7 +72,7 @@ def post(self, request, object_type, object_id):
         redirect_url = (
             reverse(url_name, kwargs={"pk": object_id})
             + f"?tab=interfaces&interface_name_field={interface_name_field}"
-            + (f"&server_key={server_key}" if server_key else "")
+            + (f"&server_key={quote_plus(server_key)}" if server_key else "")
         )
 
         if selected_interfaces is None:
diff --git a/netbox_librenms_plugin/views/sync/ip_addresses.py b/netbox_librenms_plugin/views/sync/ip_addresses.py
index 82e3e2e85d..3fb43820c0 100644
--- a/netbox_librenms_plugin/views/sync/ip_addresses.py
+++ b/netbox_librenms_plugin/views/sync/ip_addresses.py
@@ -1,3 +1,5 @@
+from urllib.parse import quote_plus
+
 from dcim.models import Device, Interface
 from django.contrib import messages
 from django.core.cache import cache
@@ -68,7 +70,7 @@ def get_ip_tab_url(self, obj):
         server_key = getattr(self, "_post_server_key", None) or self.librenms_api.server_key
         url = f"{reverse(url_name, args=[obj.pk])}?tab=ipaddresses"
         if server_key:
-            url += f"&server_key={server_key}"
+            url += f"&server_key={quote_plus(server_key)}"
         return url
 
     def post(self, request, object_type, pk):
diff --git a/netbox_librenms_plugin/views/sync/vlans.py b/netbox_librenms_plugin/views/sync/vlans.py
index 347a5deb14..f20648c88b 100644
--- a/netbox_librenms_plugin/views/sync/vlans.py
+++ b/netbox_librenms_plugin/views/sync/vlans.py
@@ -1,3 +1,5 @@
+from urllib.parse import quote_plus
+
 from dcim.models import Device
 from django.contrib import messages
 from django.core.cache import cache
@@ -69,7 +71,7 @@ def _redirect(self, object_type: str, object_id: int):
         server_key = getattr(self, "_post_server_key", None) or self.librenms_api.server_key
         url = reverse(url_name, kwargs={"pk": object_id}) + "?tab=vlans"
         if server_key:
-            url += f"&server_key={server_key}"
+            url += f"&server_key={quote_plus(server_key)}"
         return redirect(url)
 
     def _handle_create_vlans(self, request, obj, object_type, object_id):

From 7135b617585a4486f11fe3a15db90a671f4e198a Mon Sep 17 00:00:00 2001
From: Marcin Zieba <marcinpsk@gmail.com>
Date: Thu, 12 Mar 2026 16:55:48 +0100
Subject: [PATCH 12/22] =?UTF-8?q?fix(review):=20address=20PR=20#245=20Copi?=
 =?UTF-8?q?lot=20findings=20=E2=80=94=20non-positive=20ID=20guard,=20cache?=
 =?UTF-8?q?=20key=20sync=20device,=20VM=20name-sync,=20role=20reset,=20Con?=
 =?UTF-8?q?tentType=20cable=20check,=20non-blank=20form=20filter?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 docs/usage_tips/custom_field.md                     |  3 ++-
 netbox_librenms_plugin/forms.py                     | 10 +---------
 netbox_librenms_plugin/import_utils/bulk_import.py  |  6 ++++--
 .../import_utils/device_operations.py               |  6 +++---
 .../htmx/device_validation_details.html             |  2 ++
 netbox_librenms_plugin/utils.py                     |  6 ++++--
 netbox_librenms_plugin/views/base/cables_view.py    |  6 ++++--
 netbox_librenms_plugin/views/object_sync/devices.py |  1 +
 netbox_librenms_plugin/views/sync/cables.py         | 13 ++++++++++++-
 netbox_librenms_plugin/views/sync/interfaces.py     |  2 +-
 10 files changed, 34 insertions(+), 21 deletions(-)

diff --git a/docs/usage_tips/custom_field.md b/docs/usage_tips/custom_field.md
index 5891569c3e..038c1773bb 100644
--- a/docs/usage_tips/custom_field.md
+++ b/docs/usage_tips/custom_field.md
@@ -43,10 +43,11 @@ Follow these steps to create the `librenms_id` custom field in NetBox:
         ```json
         {"production": 42, "staging": 17}
         ```
-      - Legacy single-server example (integer):
+      - Legacy single-server example (integer) — read-only/deprecated; do not use for new entries:
         ```
         42
         ```
+        > Note: to create new entries manually use the JSON format shown above.
     - **Required:** Leave unchecked (optional).
     - **Default Value:** Leave blank.
 
diff --git a/netbox_librenms_plugin/forms.py b/netbox_librenms_plugin/forms.py
index 42c693a7bd..da1417b715 100644
--- a/netbox_librenms_plugin/forms.py
+++ b/netbox_librenms_plugin/forms.py
@@ -546,16 +546,8 @@ def __init__(self, *args, **kwargs):
             ]
             has_filters = any(data.get(field) for field in filter_fields)
 
-            # Option-only fields that don't constitute a real search submission
-            option_only_fields = [
-                "show_disabled",
-                "enable_vc_detection",
-                "clear_cache",
-                "exclude_existing",
-                "apply_filters",
-            ]
             non_option_fields = [
-                f for f in data if f not in option_only_fields + ["csrfmiddlewaretoken", "use_background_job"]
+                f for f in filter_fields if data.get(f) not in (None, "", []) and str(data.get(f, "")).strip()
             ]
             has_option_only = bool(data) and not bool(non_option_fields) and not has_filters
 
diff --git a/netbox_librenms_plugin/import_utils/bulk_import.py b/netbox_librenms_plugin/import_utils/bulk_import.py
index aea305cb69..abc8754190 100644
--- a/netbox_librenms_plugin/import_utils/bulk_import.py
+++ b/netbox_librenms_plugin/import_utils/bulk_import.py
@@ -7,7 +7,7 @@
 from core.choices import JobStatusChoices
 from django.core.cache import cache
 
-from ..import_validation_helpers import apply_role_to_validation, recalculate_validation_status
+from ..import_validation_helpers import apply_role_to_validation, recalculate_validation_status, remove_validation_issue
 from ..librenms_api import LibreNMSAPI
 from ..utils import find_by_librenms_id
 from .cache import get_cache_metadata_key, get_import_device_cache_key, get_validated_device_cache_key
@@ -384,7 +384,9 @@ def _refresh_existing_device(validation: dict, libre_device: dict = None, server
                 if hasattr(refreshed, "role") and refreshed.role:
                     apply_role_to_validation(validation, refreshed.role, is_vm=bool(validation.get("import_as_vm")))
                 elif not validation.get("import_as_vm"):
-                    apply_role_to_validation(validation, None)
+                    validation["device_role"] = {"found": False, "role": None}
+                    remove_validation_issue(validation, "role")
+                    validation.setdefault("issues", []).append("Device role must be manually selected before import")
                 recalculate_validation_status(validation, is_vm=bool(validation.get("import_as_vm")))
                 return
             else:
diff --git a/netbox_librenms_plugin/import_utils/device_operations.py b/netbox_librenms_plugin/import_utils/device_operations.py
index 551449c334..23a7db9b8a 100644
--- a/netbox_librenms_plugin/import_utils/device_operations.py
+++ b/netbox_librenms_plugin/import_utils/device_operations.py
@@ -309,11 +309,11 @@ def validate_device_for_import(
                 result["librenms_id_needs_migration"] = True
 
             # Check if name matches resolved name (accounts for use_sysname/strip_domain)
-            # Note: name_sync_available/suggested_name are intentionally not set for VMs
-            # because UpdateDeviceNameView only supports Device objects; VM name-sync
-            # would require a separate implementation.
             if hostname and existing_vm.name == hostname:
                 result["name_matches"] = True
+            elif hostname and existing_vm.name != hostname:
+                result["name_sync_available"] = True
+                result["suggested_name"] = hostname
 
         # Check for existing Device (by librenms_id custom field)
         if not result["existing_device"]:
diff --git a/netbox_librenms_plugin/templates/netbox_librenms_plugin/htmx/device_validation_details.html b/netbox_librenms_plugin/templates/netbox_librenms_plugin/htmx/device_validation_details.html
index ba460b6bb0..fbaa3a7597 100644
--- a/netbox_librenms_plugin/templates/netbox_librenms_plugin/htmx/device_validation_details.html
+++ b/netbox_librenms_plugin/templates/netbox_librenms_plugin/htmx/device_validation_details.html
@@ -133,6 +133,7 @@ <h6 class="card-header d-flex justify-content-between align-items-center">
                 <td>{{ validation.resolved_name|default:libre_device.sysName|default:libre_device.hostname }}</td>
               </tr>
 
+              {# Show only for non-VM contexts: true when no existing device (new import, not VM) OR when existing device is not a VM. #}
               {% if not validation.existing_device and not validation.import_as_vm or validation.existing_device and existing_device_model_name != "virtualmachine" %}
               {# Site row #}
               <tr>
@@ -206,6 +207,7 @@ <h6 class="card-header d-flex justify-content-between align-items-center">
               {% endif %}
 
               {# Serial row (only for devices) #}
+              {# Show only for non-VM contexts: true when no existing device (new import, not VM) OR when existing device is not a VM. #}
               {% if not validation.existing_device and not validation.import_as_vm or validation.existing_device and existing_device_model_name != "virtualmachine" %}
               <tr>
                 <td style="padding-left: 0.75rem;">Serial</td>
diff --git a/netbox_librenms_plugin/utils.py b/netbox_librenms_plugin/utils.py
index 869c6357bc..f63b564e50 100644
--- a/netbox_librenms_plugin/utils.py
+++ b/netbox_librenms_plugin/utils.py
@@ -535,7 +535,7 @@ def get_librenms_device_id(obj, server_key: str = "default", *, auto_save: bool
     if isinstance(cf_value, int) and not isinstance(cf_value, bool):
         # Legacy bare integer — universal fallback for any server to ensure
         # devices imported before multi-server support remain discoverable.
-        return cf_value
+        return cf_value if cf_value > 0 else None
     if isinstance(cf_value, str):
         # Someone stored a bare string (e.g., via NetBox UI/API) — normalise to int.
         # Treated as a legacy universal fallback for any server.
@@ -543,6 +543,8 @@ def get_librenms_device_id(obj, server_key: str = "default", *, auto_save: bool
             int_id = int(cf_value)
         except (ValueError, TypeError):
             return None
+        if int_id <= 0:
+            return None
         if auto_save:
             obj.custom_field_data["librenms_id"] = int_id
             obj.save(update_fields=["custom_field_data"])
@@ -563,7 +565,7 @@ def get_librenms_device_id(obj, server_key: str = "default", *, auto_save: bool
                 obj.save(update_fields=["custom_field_data"])
             return value
         if isinstance(value, int):
-            return value
+            return value if value > 0 else None
         return None
     return None
 
diff --git a/netbox_librenms_plugin/views/base/cables_view.py b/netbox_librenms_plugin/views/base/cables_view.py
index affb0a20f4..5fa9af6a91 100644
--- a/netbox_librenms_plugin/views/base/cables_view.py
+++ b/netbox_librenms_plugin/views/base/cables_view.py
@@ -309,6 +309,8 @@ def _prepare_context(self, request, obj, fetch_fresh=False):
         """Helper method to prepare the context data for cable sync views."""
         cache_expiry = None
         server_key = self.librenms_api.server_key
+        # For VC devices, cache under the sync device's key so SingleCableVerifyView reads the same entry.
+        cache_device = get_librenms_sync_device(obj, server_key=server_key) or obj
 
         if fetch_fresh:
             # Always fetch new data when requested
@@ -317,7 +319,7 @@ def _prepare_context(self, request, obj, fetch_fresh=False):
                 return None
         else:
             # Try to use cached data
-            cached_links_data = cache.get(self.get_cache_key(obj, "links", server_key))
+            cached_links_data = cache.get(self.get_cache_key(cache_device, "links", server_key))
             if cached_links_data:
                 links_data = cached_links_data.get("links", [])
             else:
@@ -341,7 +343,7 @@ def _prepare_context(self, request, obj, fetch_fresh=False):
         links_data = self.enrich_links_data(links_data, obj, server_key=server_key)
 
         # Cache after enrichment so verify/sync views read current NetBox state
-        cache_key = self.get_cache_key(obj, "links", server_key)
+        cache_key = self.get_cache_key(cache_device, "links", server_key)
         if fetch_fresh:
             cache.set(
                 cache_key,
diff --git a/netbox_librenms_plugin/views/object_sync/devices.py b/netbox_librenms_plugin/views/object_sync/devices.py
index 5b76a48cc9..6f3700af39 100644
--- a/netbox_librenms_plugin/views/object_sync/devices.py
+++ b/netbox_librenms_plugin/views/object_sync/devices.py
@@ -136,6 +136,7 @@ def post(self, request):
                     [],
                     device=selected_device,
                     interface_name_field=interface_name_field,
+                    server_key=server_key,
                 )
                 formatted_row = table.format_interface_data(port_data, selected_device)
                 return JsonResponse({"status": "success", "formatted_row": formatted_row})
diff --git a/netbox_librenms_plugin/views/sync/cables.py b/netbox_librenms_plugin/views/sync/cables.py
index 4404651d6a..7165d811da 100644
--- a/netbox_librenms_plugin/views/sync/cables.py
+++ b/netbox_librenms_plugin/views/sync/cables.py
@@ -77,8 +77,19 @@ def create_cable(self, local_interface, remote_interface, request):
 
     def check_existing_cable(self, local_interface, remote_interface):
         """Return True if a cable already exists for either interface."""
+        from django.contrib.contenttypes.models import ContentType
+        from dcim.models import Interface as DCIMInterface
+
+        interface_ct = ContentType.objects.get_for_model(DCIMInterface)
         return Cable.objects.filter(
-            Q(terminations__termination_id=local_interface.pk) | Q(terminations__termination_id=remote_interface.pk)
+            Q(
+                terminations__termination_type=interface_ct,
+                terminations__termination_id=local_interface.pk,
+            )
+            | Q(
+                terminations__termination_type=interface_ct,
+                terminations__termination_id=remote_interface.pk,
+            )
         ).exists()
 
     def validate_prerequisites(self, cached_links, selected_interfaces):
diff --git a/netbox_librenms_plugin/views/sync/interfaces.py b/netbox_librenms_plugin/views/sync/interfaces.py
index f3fe25b1ba..2259ff4892 100644
--- a/netbox_librenms_plugin/views/sync/interfaces.py
+++ b/netbox_librenms_plugin/views/sync/interfaces.py
@@ -115,7 +115,7 @@ def get_cached_ports_data(self, request, obj, server_key=None):
         # On VC member pages the GET tab writes ports under the resolved sync device's
         # cache key. Resolve the same device here so the POST path reads the same entry.
         cache_obj = obj
-        if isinstance(obj, Device) and get_librenms_device_id(obj, server_key, auto_save=False) is None:
+        if isinstance(obj, Device) and not get_librenms_device_id(obj, server_key, auto_save=False):
             sync_device = get_librenms_sync_device(obj, server_key=server_key)
             if sync_device is not None:
                 cache_obj = sync_device

From 2084076183be19d6c7a0d73cfdfe09fe606ba778 Mon Sep 17 00:00:00 2001
From: Marcin Zieba <marcinpsk@gmail.com>
Date: Thu, 12 Mar 2026 17:42:21 +0100
Subject: [PATCH 13/22] fix(review): add explicit VM VLAN opt-out, re-resolve
 cable local interface after VC override, server_key rebinding in import views

---
 .../htmx/bulk_import_confirm.html                   |  1 +
 netbox_librenms_plugin/views/imports/actions.py     | 13 +++++++++++++
 netbox_librenms_plugin/views/object_sync/vms.py     |  4 ++++
 netbox_librenms_plugin/views/sync/cables.py         |  6 ++++++
 4 files changed, 24 insertions(+)

diff --git a/netbox_librenms_plugin/templates/netbox_librenms_plugin/htmx/bulk_import_confirm.html b/netbox_librenms_plugin/templates/netbox_librenms_plugin/htmx/bulk_import_confirm.html
index ae8fdfb431..da8ba2ef65 100644
--- a/netbox_librenms_plugin/templates/netbox_librenms_plugin/htmx/bulk_import_confirm.html
+++ b/netbox_librenms_plugin/templates/netbox_librenms_plugin/htmx/bulk_import_confirm.html
@@ -131,6 +131,7 @@ <h5 class="modal-title">
         hx-target="body"
         hx-swap="none">
     {% csrf_token %}
+    <input type="hidden" name="server_key" value="{{ server_key }}">
     {% for entry in devices %}
       <input type="hidden" name="select" value="{{ entry.device_id }}">
       {% if entry.role %}<input type="hidden" name="role_{{ entry.device_id }}" value="{{ entry.role.pk }}">{% endif %}
diff --git a/netbox_librenms_plugin/views/imports/actions.py b/netbox_librenms_plugin/views/imports/actions.py
index 078db675ff..d8148262ec 100644
--- a/netbox_librenms_plugin/views/imports/actions.py
+++ b/netbox_librenms_plugin/views/imports/actions.py
@@ -311,6 +311,12 @@ def post(self, request):
         if error := self.require_write_permission():
             return error
 
+        post_server_key = request.POST.get("server_key", "").strip()
+        if post_server_key:
+            from netbox_librenms_plugin.librenms_api import LibreNMSAPI
+
+            self._librenms_api = LibreNMSAPI(server_key=post_server_key)
+
         device_ids = request.POST.getlist("select")
         if not device_ids:
             return HttpResponse(
@@ -447,6 +453,7 @@ def post(self, request):
             "errors": errors,
             "use_sysname": use_sysname,
             "strip_domain": strip_domain,
+            "server_key": self.librenms_api.server_key,
         }
 
         return render(
@@ -486,6 +493,12 @@ def post(self, request):  # noqa: PLR0912 - branching keeps responses explicit
         if error := self.require_write_permission():
             return error
 
+        post_server_key = request.POST.get("server_key", "").strip()
+        if post_server_key:
+            from netbox_librenms_plugin.librenms_api import LibreNMSAPI
+
+            self._librenms_api = LibreNMSAPI(server_key=post_server_key)
+
         device_ids = request.POST.getlist("select")
         if not device_ids:
             messages.error(request, "No devices selected for import")
diff --git a/netbox_librenms_plugin/views/object_sync/vms.py b/netbox_librenms_plugin/views/object_sync/vms.py
index a7e9e42c8d..d005aea207 100644
--- a/netbox_librenms_plugin/views/object_sync/vms.py
+++ b/netbox_librenms_plugin/views/object_sync/vms.py
@@ -35,6 +35,10 @@ def get_cable_context(self, request, obj):
         """Return None; VMs do not support cable sync."""
         return None  # VMs do not expose cable sync data
 
+    def get_vlan_context(self, request, obj):
+        """Return None; VMs do not support VLAN sync."""
+        return None
+
     def get_ip_context(self, request, obj):
         """Return IP address sync context for the virtual machine."""
         ipaddress_sync_view = VMIPAddressTableView()
diff --git a/netbox_librenms_plugin/views/sync/cables.py b/netbox_librenms_plugin/views/sync/cables.py
index 7165d811da..9664ae1061 100644
--- a/netbox_librenms_plugin/views/sync/cables.py
+++ b/netbox_librenms_plugin/views/sync/cables.py
@@ -114,6 +114,11 @@ def process_single_interface(self, interface, cached_links):
             link_data = next(link for link in cached_links if str(link.get("local_port_id", "")) == port_id)
             # Apply posted device override (VC member selection) without mutating the cached list.
             link_data = {**link_data, "device_id": interface.get("device_id", link_data.get("device_id"))}
+            # Re-resolve local interface against current NetBox state after VC member override.
+            if hasattr(self, "_initial_device"):
+                link_data.pop("netbox_local_interface_id", None)
+                link_data.pop("local_port_url", None)
+                self.enrich_local_port(link_data, self._initial_device, getattr(self, "_post_server_key", None))
             return self.handle_cable_creation(link_data, interface)
         except StopIteration:
             return {"status": "invalid", "interface": port_id}
@@ -178,6 +183,7 @@ def post(self, request, pk):
         initial_device = get_object_or_404(Device, pk=pk)
         server_key = request.POST.get("server_key") or self.librenms_api.server_key
         self._post_server_key = server_key
+        self._initial_device = initial_device
         redirect_url = (
             f"{reverse('plugins:netbox_librenms_plugin:device_librenms_sync', args=[initial_device.pk])}?tab=cables"
             + (f"&server_key={quote_plus(server_key)}" if server_key else "")

From cf4b30880a9f643010c7df1c6c57396e16392913 Mon Sep 17 00:00:00 2001
From: Marcin Zieba <marcinpsk@gmail.com>
Date: Thu, 12 Mar 2026 17:47:39 +0100
Subject: [PATCH 14/22] fix(actions): guard server_key POST value against None
 before strip()

---
 netbox_librenms_plugin/views/imports/actions.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/netbox_librenms_plugin/views/imports/actions.py b/netbox_librenms_plugin/views/imports/actions.py
index d8148262ec..fee6c43a0f 100644
--- a/netbox_librenms_plugin/views/imports/actions.py
+++ b/netbox_librenms_plugin/views/imports/actions.py
@@ -311,7 +311,7 @@ def post(self, request):
         if error := self.require_write_permission():
             return error
 
-        post_server_key = request.POST.get("server_key", "").strip()
+        post_server_key = (request.POST.get("server_key") or "").strip()
         if post_server_key:
             from netbox_librenms_plugin.librenms_api import LibreNMSAPI
 
@@ -493,7 +493,7 @@ def post(self, request):  # noqa: PLR0912 - branching keeps responses explicit
         if error := self.require_write_permission():
             return error
 
-        post_server_key = request.POST.get("server_key", "").strip()
+        post_server_key = (request.POST.get("server_key") or "").strip()
         if post_server_key:
             from netbox_librenms_plugin.librenms_api import LibreNMSAPI
 
@@ -1006,7 +1006,7 @@ def post(self, request, device_id):
 
         # If the form submitted a specific server_key, honour it so the handler uses
         # the same server context as the import page when the user clicked the button.
-        post_server_key = request.POST.get("server_key", "").strip()
+        post_server_key = (request.POST.get("server_key") or "").strip()
         if post_server_key:
             self._librenms_api = LibreNMSAPI(server_key=post_server_key)
 

From 38ca2c57b4d014be4f225032c5a2727e82c10ef5 Mon Sep 17 00:00:00 2001
From: Marcin Zieba <marcinpsk@gmail.com>
Date: Thu, 12 Mar 2026 17:56:45 +0100
Subject: [PATCH 15/22] fix(cables): only re-resolve local interface on
 explicit VC override; move ContentType import to module level

---
 netbox_librenms_plugin/views/sync/cables.py | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/netbox_librenms_plugin/views/sync/cables.py b/netbox_librenms_plugin/views/sync/cables.py
index 9664ae1061..883879fc39 100644
--- a/netbox_librenms_plugin/views/sync/cables.py
+++ b/netbox_librenms_plugin/views/sync/cables.py
@@ -3,6 +3,7 @@
 
 from dcim.models import Cable, Device, Interface
 from django.contrib import messages
+from django.contrib.contenttypes.models import ContentType
 from django.core.cache import cache
 from django.db import transaction
 from django.db.models import Q
@@ -44,8 +45,11 @@ def get_selected_interfaces(self, request, initial_device):
             return None
 
         for port_id in selected_data:
-            device_id = request.POST.get(f"device_selection_{port_id}") or initial_device.id
-            selected_interfaces.append({"device_id": device_id, "local_port_id": port_id})
+            override = request.POST.get(f"device_selection_{port_id}")
+            device_id = override or initial_device.id
+            selected_interfaces.append(
+                {"device_id": device_id, "local_port_id": port_id, "vc_override": bool(override)}
+            )
 
         return selected_interfaces
 
@@ -77,7 +81,6 @@ def create_cable(self, local_interface, remote_interface, request):
 
     def check_existing_cable(self, local_interface, remote_interface):
         """Return True if a cable already exists for either interface."""
-        from django.contrib.contenttypes.models import ContentType
         from dcim.models import Interface as DCIMInterface
 
         interface_ct = ContentType.objects.get_for_model(DCIMInterface)
@@ -114,8 +117,8 @@ def process_single_interface(self, interface, cached_links):
             link_data = next(link for link in cached_links if str(link.get("local_port_id", "")) == port_id)
             # Apply posted device override (VC member selection) without mutating the cached list.
             link_data = {**link_data, "device_id": interface.get("device_id", link_data.get("device_id"))}
-            # Re-resolve local interface against current NetBox state after VC member override.
-            if hasattr(self, "_initial_device"):
+            # Re-resolve local interface only when a VC member override was explicitly applied.
+            if interface.get("vc_override") and hasattr(self, "_initial_device"):
                 link_data.pop("netbox_local_interface_id", None)
                 link_data.pop("local_port_url", None)
                 self.enrich_local_port(link_data, self._initial_device, getattr(self, "_post_server_key", None))

From 1b4051f476925fab40f193acc2459180797ac927 Mon Sep 17 00:00:00 2001
From: Marcin Zieba <marcinpsk@gmail.com>
Date: Thu, 12 Mar 2026 18:50:00 +0100
Subject: [PATCH 16/22] fix(verify-views): VC guard for sync device resolution;
 hw_match None guard in actions

---
 netbox_librenms_plugin/tests/test_verify_views.py   |  7 ++++---
 netbox_librenms_plugin/views/base/cables_view.py    | 11 ++++++++---
 netbox_librenms_plugin/views/imports/actions.py     |  2 +-
 netbox_librenms_plugin/views/object_sync/devices.py | 13 ++++++++++---
 4 files changed, 23 insertions(+), 10 deletions(-)

diff --git a/netbox_librenms_plugin/tests/test_verify_views.py b/netbox_librenms_plugin/tests/test_verify_views.py
index 4007f04f76..e8ecf4b9fb 100644
--- a/netbox_librenms_plugin/tests/test_verify_views.py
+++ b/netbox_librenms_plugin/tests/test_verify_views.py
@@ -6,7 +6,7 @@
 """
 
 import json
-from unittest.mock import MagicMock, patch
+from unittest.mock import ANY, MagicMock, patch
 
 
 def _make_request(body: dict) -> MagicMock:
@@ -75,7 +75,7 @@ def test_vc_resolved_sync_device_uses_cache(self, mock_cache, mock_sync, mock_ge
         request = _make_request({"device_id": 1, "local_port_id": "42"})
         view.post(request)
 
-        mock_sync.assert_called_once_with(device)
+        mock_sync.assert_called_once_with(device, server_key=ANY)
         mock_cache.get.assert_called_once()
         cache_key = mock_cache.get.call_args[0][0]
         assert "device" in cache_key
@@ -118,6 +118,7 @@ def _make_view(self):
         from netbox_librenms_plugin.views.object_sync.devices import SingleInterfaceVerifyView
 
         view = object.__new__(SingleInterfaceVerifyView)
+        view._librenms_api = MagicMock()
         return view
 
     @patch("netbox_librenms_plugin.views.object_sync.devices.get_object_or_404")
@@ -166,7 +167,7 @@ def test_vc_resolved_sync_device_uses_cache(self, mock_cache, mock_sync, mock_ge
         )
         view.post(request)
 
-        mock_sync.assert_called_once_with(device)
+        mock_sync.assert_called_once_with(device, server_key=ANY)
         mock_cache.get.assert_called_once()
         cache_key = mock_cache.get.call_args[0][0]
         assert "3" in cache_key
diff --git a/netbox_librenms_plugin/views/base/cables_view.py b/netbox_librenms_plugin/views/base/cables_view.py
index 5fa9af6a91..938ad01fb8 100644
--- a/netbox_librenms_plugin/views/base/cables_view.py
+++ b/netbox_librenms_plugin/views/base/cables_view.py
@@ -430,9 +430,14 @@ def post(self, request):
         if selected_device_id:
             selected_device = get_object_or_404(Device, pk=selected_device_id)
 
-            # Use the same sync-device resolution as the GET path so the cache
-            # key matches what _prepare_context wrote.
-            primary_device = get_librenms_sync_device(selected_device, server_key=server_key) or selected_device
+            # For VC devices, resolve to the primary sync device so the cache key
+            # matches what _prepare_context wrote; return empty row if unresolvable.
+            if hasattr(selected_device, "virtual_chassis") and selected_device.virtual_chassis:
+                primary_device = get_librenms_sync_device(selected_device, server_key=server_key)
+                if primary_device is None:
+                    return JsonResponse({"status": "success", "formatted_row": formatted_row})
+            else:
+                primary_device = selected_device
 
             cached_links = cache.get(self.get_cache_key(primary_device, "links", server_key))
 
diff --git a/netbox_librenms_plugin/views/imports/actions.py b/netbox_librenms_plugin/views/imports/actions.py
index fee6c43a0f..fa60ef6ef8 100644
--- a/netbox_librenms_plugin/views/imports/actions.py
+++ b/netbox_librenms_plugin/views/imports/actions.py
@@ -1277,7 +1277,7 @@ def post(self, request, device_id):
 
             hardware = libre_device.get("hardware") or ""
             hw_match = match_librenms_hardware_to_device_type(hardware)
-            if hw_match.get("matched"):
+            if hw_match and hw_match.get("matched"):
                 existing_device.device_type = hw_match["device_type"]
                 if err := _save_device(existing_device):
                     return err
diff --git a/netbox_librenms_plugin/views/object_sync/devices.py b/netbox_librenms_plugin/views/object_sync/devices.py
index 6f3700af39..b47d076120 100644
--- a/netbox_librenms_plugin/views/object_sync/devices.py
+++ b/netbox_librenms_plugin/views/object_sync/devices.py
@@ -117,9 +117,16 @@ def post(self, request):
 
         selected_device = get_object_or_404(Device, pk=selected_device_id)
 
-        # Normalise to the VC sync device so cache keys match what the sync view stored
-        primary_device = get_librenms_sync_device(selected_device, server_key=server_key)
-        if primary_device is None:
+        # For VC devices, resolve to the primary sync device so cache keys match;
+        # return 404 if the VC has no resolvable sync device.
+        if hasattr(selected_device, "virtual_chassis") and selected_device.virtual_chassis:
+            primary_device = get_librenms_sync_device(selected_device, server_key=server_key)
+            if primary_device is None:
+                return JsonResponse(
+                    {"status": "error", "message": "Cannot resolve sync device for this virtual chassis"},
+                    status=404,
+                )
+        else:
             primary_device = selected_device
 
         cached_data = cache.get(self.get_cache_key(primary_device, "ports", server_key))

From e72ec2ae5dd5d82a410977f1375da18ac8138fbb Mon Sep 17 00:00:00 2001
From: Marcin Zieba <marcinpsk@gmail.com>
Date: Thu, 12 Mar 2026 19:14:35 +0100
Subject: [PATCH 17/22] Fix chassis_member None guard, get_cached_links_data VC
 key, test_view_wiring

- cables_view.py: guard chassis_member None before .interfaces access in
  enrich_local_port and enrich_remote_port
- sync/cables.py: get_cached_links_data now resolves VC-normalized device
  via get_librenms_sync_device before building cache key, matching
  _prepare_context and SingleCableVerifyView.post
- test_view_wiring.py: patch get_librenms_sync_device to return mock_device
  so VC guard passes and cache.get is reachable
---
 .../tests/test_view_wiring.py                 |  7 +++--
 .../views/base/cables_view.py                 | 30 ++++++++++---------
 netbox_librenms_plugin/views/sync/cables.py   |  4 ++-
 3 files changed, 23 insertions(+), 18 deletions(-)

diff --git a/netbox_librenms_plugin/tests/test_view_wiring.py b/netbox_librenms_plugin/tests/test_view_wiring.py
index 3c24202c32..a79bb0a3d9 100644
--- a/netbox_librenms_plugin/tests/test_view_wiring.py
+++ b/netbox_librenms_plugin/tests/test_view_wiring.py
@@ -405,11 +405,11 @@ def test_server_key_used_for_cache_lookup(self):
             patch("netbox_librenms_plugin.views.base.cables_view.get_object_or_404") as mock_get_obj,
             patch(
                 "netbox_librenms_plugin.views.base.cables_view.get_librenms_sync_device",
-                return_value=None,
             ) as mock_sync_device,
             patch("netbox_librenms_plugin.views.base.cables_view.cache") as mock_cache,
         ):
             mock_device = MagicMock()
+            mock_sync_device.return_value = mock_device  # return a device so code reaches cache.get
             mock_get_obj.return_value = mock_device
             mock_cache.get.return_value = None  # No cached data
 
@@ -443,11 +443,12 @@ def test_fallback_to_api_server_key(self):
             patch("netbox_librenms_plugin.views.base.cables_view.get_object_or_404") as mock_get_obj,
             patch(
                 "netbox_librenms_plugin.views.base.cables_view.get_librenms_sync_device",
-                return_value=None,
             ) as mock_sync_device,
             patch("netbox_librenms_plugin.views.base.cables_view.cache") as mock_cache,
         ):
-            mock_get_obj.return_value = MagicMock()
+            mock_device = MagicMock()
+            mock_sync_device.return_value = mock_device  # return a device so code reaches cache.get
+            mock_get_obj.return_value = mock_device
             mock_cache.get.return_value = None
 
             view.post(request)
diff --git a/netbox_librenms_plugin/views/base/cables_view.py b/netbox_librenms_plugin/views/base/cables_view.py
index 938ad01fb8..043a01b6af 100644
--- a/netbox_librenms_plugin/views/base/cables_view.py
+++ b/netbox_librenms_plugin/views/base/cables_view.py
@@ -166,13 +166,14 @@ def enrich_local_port(self, link, obj, server_key=None):
             if hasattr(obj, "virtual_chassis") and obj.virtual_chassis:
                 chassis_member = get_virtual_chassis_member(obj, local_port)
 
-                # First try to find interface by librenms_id
-                if local_port_id:
-                    interface = chassis_member.interfaces.filter(_librenms_id_q(server_key, local_port_id)).first()
+                if chassis_member:
+                    # First try to find interface by librenms_id
+                    if local_port_id:
+                        interface = chassis_member.interfaces.filter(_librenms_id_q(server_key, local_port_id)).first()
 
-                # Only if librenms_id match fails, try matching by name
-                if not interface:
-                    interface = chassis_member.interfaces.filter(name=local_port).first()
+                    # Only if librenms_id match fails, try matching by name
+                    if not interface:
+                        interface = chassis_member.interfaces.filter(name=local_port).first()
             else:
                 # First try to find interface by librenms_id
                 if local_port_id:
@@ -199,15 +200,16 @@ def enrich_remote_port(self, link, device, server_key=None):
                 # Get the appropriate chassis member based on the port name
                 chassis_member = get_virtual_chassis_member(device, remote_port)
 
-                # First try to find interface by librenms_id
-                if librenms_remote_port_id:
-                    netbox_remote_interface = chassis_member.interfaces.filter(
-                        _librenms_id_q(server_key, librenms_remote_port_id)
-                    ).first()
+                if chassis_member:
+                    # First try to find interface by librenms_id
+                    if librenms_remote_port_id:
+                        netbox_remote_interface = chassis_member.interfaces.filter(
+                            _librenms_id_q(server_key, librenms_remote_port_id)
+                        ).first()
 
-                # If not found by librenms_id, fall back to name matching on the correct chassis member
-                if not netbox_remote_interface:
-                    netbox_remote_interface = chassis_member.interfaces.filter(name=remote_port).first()
+                    # If not found by librenms_id, fall back to name matching on the correct chassis member
+                    if not netbox_remote_interface:
+                        netbox_remote_interface = chassis_member.interfaces.filter(name=remote_port).first()
             else:
                 # Non-virtual chassis case
                 # First try to find interface by librenms_id
diff --git a/netbox_librenms_plugin/views/sync/cables.py b/netbox_librenms_plugin/views/sync/cables.py
index 883879fc39..1b46d7310c 100644
--- a/netbox_librenms_plugin/views/sync/cables.py
+++ b/netbox_librenms_plugin/views/sync/cables.py
@@ -11,6 +11,7 @@
 from django.urls import reverse
 from django.views import View
 
+from netbox_librenms_plugin.utils import get_librenms_sync_device
 from netbox_librenms_plugin.views.mixins import (
     CacheMixin,
     LibreNMSAPIMixin,
@@ -56,7 +57,8 @@ def get_selected_interfaces(self, request, initial_device):
     def get_cached_links_data(self, request, obj):
         """Return cached LibreNMS link data for the given object."""
         server_key = getattr(self, "_post_server_key", None) or self.librenms_api.server_key
-        cached_data = cache.get(self.get_cache_key(obj, "links", server_key))
+        cache_obj = get_librenms_sync_device(obj, server_key=server_key) or obj
+        cached_data = cache.get(self.get_cache_key(cache_obj, "links", server_key))
         if not cached_data:
             return None
         return cached_data.get("links", [])

From f158c0d3976a3385a4abb5405e7bd636a1f917cc Mon Sep 17 00:00:00 2001
From: Marcin Zieba <marcinpsk@gmail.com>
Date: Thu, 12 Mar 2026 19:33:06 +0100
Subject: [PATCH 18/22] fix(cables): correct VC member interface resolution in
 SyncCablesView
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

- get_selected_interfaces: remove vc_override flag; device_selection_<port_id>
  is always posted for VC rows so bool(override) was always True, making the
  flag meaningless
- process_single_interface: remove broken enrich_local_port block; SyncCablesView
  does not inherit BaseCableTableView so the method did not exist, and it
  resolved against _initial_device (full chassis) not the selected member
- handle_cable_creation: add VC-aware re-lookup — after fetching the cached
  local_interface, compare its device_id to the posted device_id; if different,
  re-query Interface by (device_id, name) so the user's selected VC member
  drives the cable endpoint
---
 netbox_librenms_plugin/views/sync/cables.py | 26 ++++++++++++++-------
 1 file changed, 17 insertions(+), 9 deletions(-)

diff --git a/netbox_librenms_plugin/views/sync/cables.py b/netbox_librenms_plugin/views/sync/cables.py
index 1b46d7310c..692bbaf1fc 100644
--- a/netbox_librenms_plugin/views/sync/cables.py
+++ b/netbox_librenms_plugin/views/sync/cables.py
@@ -48,9 +48,7 @@ def get_selected_interfaces(self, request, initial_device):
         for port_id in selected_data:
             override = request.POST.get(f"device_selection_{port_id}")
             device_id = override or initial_device.id
-            selected_interfaces.append(
-                {"device_id": device_id, "local_port_id": port_id, "vc_override": bool(override)}
-            )
+            selected_interfaces.append({"device_id": device_id, "local_port_id": port_id})
 
         return selected_interfaces
 
@@ -117,13 +115,8 @@ def process_single_interface(self, interface, cached_links):
         port_id = str(interface.get("local_port_id", ""))
         try:
             link_data = next(link for link in cached_links if str(link.get("local_port_id", "")) == port_id)
-            # Apply posted device override (VC member selection) without mutating the cached list.
+            # Apply posted device_id (VC member selection) without mutating the cached list.
             link_data = {**link_data, "device_id": interface.get("device_id", link_data.get("device_id"))}
-            # Re-resolve local interface only when a VC member override was explicitly applied.
-            if interface.get("vc_override") and hasattr(self, "_initial_device"):
-                link_data.pop("netbox_local_interface_id", None)
-                link_data.pop("local_port_url", None)
-                self.enrich_local_port(link_data, self._initial_device, getattr(self, "_post_server_key", None))
             return self.handle_cable_creation(link_data, interface)
         except StopIteration:
             return {"status": "invalid", "interface": port_id}
@@ -147,6 +140,21 @@ def handle_cable_creation(self, link_data, interface):
 
         try:
             local_interface = Interface.objects.get(pk=link_data["netbox_local_interface_id"])
+
+            # Honour user's VC member selection: if the selected device_id differs from
+            # the cached interface's device, look up the same port name on that device.
+            selected_device_id = interface.get("device_id")
+            if selected_device_id and str(local_interface.device_id) != str(selected_device_id):
+                port_name = link_data.get("local_port") or local_interface.name
+                try:
+                    local_interface = Interface.objects.get(device_id=selected_device_id, name=port_name)
+                except Interface.DoesNotExist:
+                    logger.debug(
+                        "Port %s not found on device %s; falling back to cached interface",
+                        port_name,
+                        selected_device_id,
+                    )
+
             remote_interface = Interface.objects.get(pk=link_data["netbox_remote_interface_id"])
 
             if self.check_existing_cable(local_interface, remote_interface):

From 3ced0b4d1ba3cdaf8e6a6e6e225a4c0dfc05e1bc Mon Sep 17 00:00:00 2001
From: Marcin Zieba <marcinpsk@gmail.com>
Date: Thu, 12 Mar 2026 20:35:09 +0100
Subject: [PATCH 19/22] chore: restore develop versions of PR template,
 pre-commit config, pyproject.toml; remove uv.lock

Restore files that diverged from upstream/develop so they don't appear
as deletions/modifications in the PR diff:
- .github/pull_request_template.md: was deleted, restore from develop
- .pre-commit-config.yaml: restore develop version
- pyproject.toml: restore develop version
- uv.lock: remove (not present in develop)
---
 .github/pull_request_template.md | 49 ++++++++++++++++++++++++++++++++
 .pre-commit-config.yaml          |  6 +---
 pyproject.toml                   |  6 ----
 uv.lock                          |  8 ------
 4 files changed, 50 insertions(+), 19 deletions(-)
 create mode 100644 .github/pull_request_template.md
 delete mode 100644 uv.lock

diff --git a/.github/pull_request_template.md b/.github/pull_request_template.md
new file mode 100644
index 0000000000..99ff02374f
--- /dev/null
+++ b/.github/pull_request_template.md
@@ -0,0 +1,49 @@
+## Summary
+Briefly describe what this PR does in plain English, and provide as much of the following information as possible.
+
+## Motivation / Problem
+What issue does this solve?
+- Bug
+- Feature
+- Refactor
+- Maintenance / cleanup
+
+Link any related issues if applicable.
+
+## Scope of Change
+Delete items that don’t apply:
+
+- Sync/Import logic
+- NetBox models / ORM
+- LibreNMS API interaction
+- Config / settings
+- Web UI / templates
+- Database migrations
+- Tests
+- Docs only
+- Other: <describe>
+
+## How Was This Tested?
+Delete items that don’t apply and describe briefly.
+
+- Unit tests: <yes/no + what>
+- Manual testing: <yes/no + what>
+- Not tested: <explain why>
+
+### Manual Test Steps (if applicable)
+1.
+2.
+3.
+
+## Risk Assessment
+- Does this change affect existing users?
+- Could this cause unintended imports / updates?
+
+Explain briefly.
+
+## Backwards Compatibility
+- No breaking changes
+- Breaking change (explain and document)
+
+## Other Notes
+Anything the maintainer(s) should pay particular attention to?
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 7346e658ed..6669696bbb 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -1,6 +1,6 @@
 repos:
   - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.15.5  # Use the latest version from https://github.com/astral-sh/ruff-pre-commit/releases
+    rev: v0.15.4  # Use the latest version from https://github.com/astral-sh/ruff-pre-commit/releases
     hooks:
       # Run the linter
       - id: ruff-check
@@ -15,9 +15,5 @@ repos:
       - id: end-of-file-fixer
       - id: check-yaml
         exclude: ^mkdocs\.yml$
-      - id: check-yaml
-        name: check-yaml (mkdocs.yml --unsafe)
-        args: [--unsafe]
-        files: ^mkdocs\.yml$
       - id: check-added-large-files
       - id: check-merge-conflict
diff --git a/pyproject.toml b/pyproject.toml
index 43f998dee1..141a9f78f1 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -46,12 +46,6 @@ python_classes = "Test*"
 python_functions = "test_*"
 addopts = "-v --tb=short"
 
-[tool.coverage.run]
-omit = [
-    "*/tests/*",
-    "*/test_*.py",
-]
-
 [tool.ruff]
 line-length = 120
 
diff --git a/uv.lock b/uv.lock
deleted file mode 100644
index 32ce70698f..0000000000
--- a/uv.lock
+++ /dev/null
@@ -1,8 +0,0 @@
-version = 1
-revision = 3
-requires-python = ">=3.12.0"
-
-[[package]]
-name = "netbox-librenms-plugin"
-version = "0.4.3"
-source = { editable = "." }

From 18fd0ebdd015a82ac50837f22bdda7c255994b0b Mon Sep 17 00:00:00 2001
From: Marcin Zieba <marcinpsk@gmail.com>
Date: Thu, 12 Mar 2026 21:49:45 +0100
Subject: [PATCH 20/22] chore(tests): remove orphaned import_single_device
 comment header (test lives in test_import_utils.py)

---
 netbox_librenms_plugin/tests/test_view_wiring.py | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/netbox_librenms_plugin/tests/test_view_wiring.py b/netbox_librenms_plugin/tests/test_view_wiring.py
index a79bb0a3d9..8c3ceda9fb 100644
--- a/netbox_librenms_plugin/tests/test_view_wiring.py
+++ b/netbox_librenms_plugin/tests/test_view_wiring.py
@@ -458,8 +458,3 @@ def test_fallback_to_api_server_key(self):
             # cache lookup must also use the fallback server_key
             cache_key_arg = mock_cache.get.call_args[0][0]
             assert "fallback-server" in cache_key_arg
-
-
-# ---------------------------------------------------------------------------
-# import_single_device — lazy validation passes api
-# ---------------------------------------------------------------------------

From 3da9bb020a8b98acda8bcb37562317ce704de820 Mon Sep 17 00:00:00 2001
From: Marcin Zieba <marcinpsk@gmail.com>
Date: Wed, 18 Mar 2026 18:11:40 +0100
Subject: [PATCH 21/22] feat(migrations): add migration to convert librenms_id
 to JSON for multi-server support

---
 .../0009_convert_librenms_id_to_json.py       | 52 +++++++++++++++++++
 1 file changed, 52 insertions(+)
 create mode 100644 netbox_librenms_plugin/migrations/0009_convert_librenms_id_to_json.py

diff --git a/netbox_librenms_plugin/migrations/0009_convert_librenms_id_to_json.py b/netbox_librenms_plugin/migrations/0009_convert_librenms_id_to_json.py
new file mode 100644
index 0000000000..893d7dfedb
--- /dev/null
+++ b/netbox_librenms_plugin/migrations/0009_convert_librenms_id_to_json.py
@@ -0,0 +1,52 @@
+"""
+Convert the ``librenms_id`` custom field type from integer to JSON.
+
+Multi-server support stores ``librenms_id`` as a JSON dict
+(``{"server_key": device_id, …}``).  Installations created before this
+change will have the custom field defined as type *integer*.  This
+migration updates the CustomField type so that NetBox validation accepts
+the new dict format.
+
+Existing bare-integer **values** on devices/VMs/interfaces are left
+untouched — they are migrated to the dict format on a per-object basis
+through the admin UI / API (see ``migrate_legacy_librenms_id`` in utils).
+"""
+
+from django.db import migrations
+
+
+def _convert_librenms_id_to_json(apps, schema_editor):
+    CustomField = apps.get_model("extras", "CustomField")
+    try:
+        cf = CustomField.objects.get(name="librenms_id")
+    except CustomField.DoesNotExist:
+        # Custom field hasn't been created yet — nothing to convert.
+        return
+    if cf.type == "integer":
+        cf.type = "json"
+        cf.save(update_fields=["type"])
+
+
+def _revert_librenms_id_to_integer(apps, schema_editor):
+    CustomField = apps.get_model("extras", "CustomField")
+    try:
+        cf = CustomField.objects.get(name="librenms_id")
+    except CustomField.DoesNotExist:
+        return
+    if cf.type == "json":
+        cf.type = "integer"
+        cf.save(update_fields=["type"])
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("extras", "0001_initial"),
+        ("netbox_librenms_plugin", "0008_librenmssettings_import_defaults"),
+    ]
+
+    operations = [
+        migrations.RunPython(
+            code=_convert_librenms_id_to_json,
+            reverse_code=_revert_librenms_id_to_integer,
+        ),
+    ]

From 92b03012fbd53a2d26961fa21e7c68694647a451 Mon Sep 17 00:00:00 2001
From: Marcin Zieba <marcinpsk@gmail.com>
Date: Wed, 18 Mar 2026 21:29:13 +0100
Subject: [PATCH 22/22] fix(migrations): use db_alias for multi-db safety;
 guard reverse against existing JSON values

---
 .../0009_convert_librenms_id_to_json.py       | 33 ++++++++++++++++---
 1 file changed, 29 insertions(+), 4 deletions(-)

diff --git a/netbox_librenms_plugin/migrations/0009_convert_librenms_id_to_json.py b/netbox_librenms_plugin/migrations/0009_convert_librenms_id_to_json.py
index 893d7dfedb..f8194cb06e 100644
--- a/netbox_librenms_plugin/migrations/0009_convert_librenms_id_to_json.py
+++ b/netbox_librenms_plugin/migrations/0009_convert_librenms_id_to_json.py
@@ -16,26 +16,51 @@
 
 
 def _convert_librenms_id_to_json(apps, schema_editor):
+    db_alias = schema_editor.connection.alias
     CustomField = apps.get_model("extras", "CustomField")
     try:
-        cf = CustomField.objects.get(name="librenms_id")
+        cf = CustomField.objects.using(db_alias).get(name="librenms_id")
     except CustomField.DoesNotExist:
         # Custom field hasn't been created yet — nothing to convert.
         return
     if cf.type == "integer":
         cf.type = "json"
-        cf.save(update_fields=["type"])
+        cf.save(using=db_alias, update_fields=["type"])
 
 
 def _revert_librenms_id_to_integer(apps, schema_editor):
+    db_alias = schema_editor.connection.alias
     CustomField = apps.get_model("extras", "CustomField")
     try:
-        cf = CustomField.objects.get(name="librenms_id")
+        cf = CustomField.objects.using(db_alias).get(name="librenms_id")
     except CustomField.DoesNotExist:
         return
+
+    # Prevent unsafe downgrade if JSON-scoped values already exist.
+    models_to_check = [
+        ("dcim", "Device"),
+        ("virtualization", "VirtualMachine"),
+        ("dcim", "Interface"),
+        ("virtualization", "VMInterface"),
+    ]
+    for app_label, model_name in models_to_check:
+        Model = apps.get_model(app_label, model_name)
+        for value in (
+            Model.objects.using(db_alias)
+            .exclude(custom_field_data__librenms_id=None)
+            .values_list("custom_field_data__librenms_id", flat=True)
+            .iterator()
+        ):
+            if isinstance(value, dict):
+                raise RuntimeError(
+                    "Cannot reverse librenms_id CustomField to integer: "
+                    "JSON-scoped values already exist. Migrate them back to "
+                    "bare integers first."
+                )
+
     if cf.type == "json":
         cf.type = "integer"
-        cf.save(update_fields=["type"])
+        cf.save(using=db_alias, update_fields=["type"])
 
 
 class Migration(migrations.Migration):