diff --git a/CHANGELOG.md b/CHANGELOG.md
index 603b222..97244f9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## major.minor.patch (yyyy.mm.dd)
 
+### Fixed
+
+* Do not attach a body to bodyless requests. `encode_body/1` serialized a nil body to the literal `"null"`, so every GET/DELETE carried a JSON body. Older HTTP clients dropped it, but Req >= 0.7 transmits it and Typesense returns 404 for a GET-with-body (e.g. `get_collection` on `/collections/:name`), breaking collection existence checks and reindexing.
+
 ## 1.3.5 (2026.06.09)
 
 ### Chore
diff --git a/lib/open_api_typesense/client.ex b/lib/open_api_typesense/client.ex
index 7488ec1..aa7c757 100644
--- a/lib/open_api_typesense/client.ex
+++ b/lib/open_api_typesense/client.ex
@@ -123,6 +123,14 @@ defmodule OpenApiTypesense.Client do
       |> scrub_data()
 
     case {opts[:request], body} do
+      # No request-body spec and no body (e.g. GET/DELETE) — send no body at all.
+      # Encoding `nil` to the literal "null" makes bodyless requests carry a JSON body, which
+      # older HTTP clients silently dropped but Req >= 0.7 transmits. Typesense then returns 404
+      # for a GET-with-body on routes like `/collections/:name`, so `get_collection` cannot see a
+      # collection that exists. Returning nil lets Req omit the body.
+      {nil, nil} ->
+        nil
+
       {nil, _} ->
         Jason.encode_to_iodata!(body)
 
diff --git a/test/default_client_test.exs b/test/default_client_test.exs
index 658f7b1..7ea624d 100644
--- a/test/default_client_test.exs
+++ b/test/default_client_test.exs
@@ -57,6 +57,23 @@ defmodule DefaultClientTest do
                max_retries: 0
              }
     end
+
+    @tag [
+      "30.1": true,
+      "30.0": true,
+      "29.0": true,
+      "28.0": true,
+      "27.1": true,
+      "27.0": true,
+      "26.0": true
+    ]
+    test "does not attach a body to bodyless requests" do
+      # A GET/DELETE with no body must not carry the literal "null" — Req >= 0.7 transmits it and
+      # Typesense 404s a GET-with-body (e.g. get_collection). See encode_body/1.
+      req = Client.build_req_client(Connection.new(), url: "/collections/foo", method: :get)
+
+      assert req.body == nil
+    end
   end
 
   @tag [