diff --git a/.sampo/changesets/resolute-guardian-ilmarinen.md b/.sampo/changesets/resolute-guardian-ilmarinen.md
new file mode 100644
index 00000000..2ae86e58
--- /dev/null
+++ b/.sampo/changesets/resolute-guardian-ilmarinen.md
@@ -0,0 +1,5 @@
+---
+pypi/posthog: patch
+---
+
+add PROPERTY_OPERATORS constant for match_property
diff --git a/posthog/feature_flags.py b/posthog/feature_flags.py
index 5a5bf8e9..acd2d999 100644
--- a/posthog/feature_flags.py
+++ b/posthog/feature_flags.py
@@ -18,6 +18,30 @@
 
 NONE_VALUES_ALLOWED_OPERATORS = ["is_not"]
 
+# All operators supported by match_property, grouped by category.
+EQUALITY_OPERATORS = ("exact", "is_not", "is_set", "is_not_set")
+STRING_OPERATORS = ("icontains", "not_icontains", "regex", "not_regex")
+NUMERIC_OPERATORS = ("gt", "gte", "lt", "lte")
+DATE_OPERATORS = ("is_date_before", "is_date_after")
+SEMVER_COMPARISON_OPERATORS = (
+    "semver_eq",
+    "semver_neq",
+    "semver_gt",
+    "semver_gte",
+    "semver_lt",
+    "semver_lte",
+)
+SEMVER_RANGE_OPERATORS = ("semver_tilde", "semver_caret", "semver_wildcard")
+SEMVER_OPERATORS = SEMVER_COMPARISON_OPERATORS + SEMVER_RANGE_OPERATORS
+
+PROPERTY_OPERATORS = (
+    EQUALITY_OPERATORS
+    + STRING_OPERATORS
+    + NUMERIC_OPERATORS
+    + DATE_OPERATORS
+    + SEMVER_OPERATORS
+)
+
 
 class InconclusiveMatchError(Exception):
     pass
@@ -385,6 +409,9 @@ def match_property(property, property_values) -> bool:
     operator = property.get("operator") or "exact"
     value = property.get("value")
 
+    if operator not in PROPERTY_OPERATORS:
+        raise InconclusiveMatchError(f"Unknown operator {operator}")
+
     if key not in property_values:
         raise InconclusiveMatchError(
             "can't match properties without a given property value"
@@ -505,17 +532,7 @@ def compare(lhs, rhs, operator):
                 "The date provided must be a string or date object"
             )
 
-    if operator in (
-        "semver_eq",
-        "semver_neq",
-        "semver_gt",
-        "semver_gte",
-        "semver_lt",
-        "semver_lte",
-        "semver_tilde",
-        "semver_caret",
-        "semver_wildcard",
-    ):
+    if operator in SEMVER_OPERATORS:
         try:
             override_parsed = parse_semver(override_value)
         except (ValueError, TypeError):
@@ -523,14 +540,7 @@ def compare(lhs, rhs, operator):
                 f"Person property value '{override_value}' is not a valid semver"
             )
 
-        if operator in (
-            "semver_eq",
-            "semver_neq",
-            "semver_gt",
-            "semver_gte",
-            "semver_lt",
-            "semver_lte",
-        ):
+        if operator in SEMVER_COMPARISON_OPERATORS:
             try:
                 flag_parsed = parse_semver(value)
             except (ValueError, TypeError):
@@ -578,7 +588,8 @@ def compare(lhs, rhs, operator):
                 )
             return lower <= override_parsed < upper
 
-    # if we get here, we don't know how to handle the operator
+    # Unreachable: all operators in PROPERTY_OPERATORS are handled above,
+    # and unknown operators are rejected at the top of this function.
     raise InconclusiveMatchError(f"Unknown operator {operator}")