diff --git a/CHANGELOG.md b/CHANGELOG.md
index fce3496..f084123 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,7 +2,7 @@
 
 ### Bug fixes
 
-- Validation error path field can be empty
+- Validation error path field can be empty (#52)
 
 ## v0.10.5 (2024-03-07)
 
diff --git a/cerbos/sdk/_async/_http.py b/cerbos/sdk/_async/_http.py
index 3de54c7..09994f1 100644
--- a/cerbos/sdk/_async/_http.py
+++ b/cerbos/sdk/_async/_http.py
@@ -196,7 +196,12 @@ async def check_resources(
             resources=resources.resources,
             aux_data=aux_data,
         )
-        resp = await self._http.post("/api/check/resources", json=req.to_dict())
+
+        # omit keys with `None` values
+        resp = await self._http.post(
+            "/api/check/resources",
+            json={k: v for k, v in req.to_dict().items() if v is not None},
+        )
         if resp.is_error:
             if self._raise_on_error:
                 raise CerbosRequestException(APIError.from_dict(resp.json()))
@@ -265,7 +270,10 @@ async def plan_resources(
             aux_data=aux_data,
         )
 
-        resp = await self._http.post("/api/plan/resources", json=req.to_dict())
+        resp = await self._http.post(
+            "/api/plan/resources",
+            json={k: v for k, v in req.to_dict().items() if v is not None},
+        )
         if resp.is_error:
             if self._raise_on_error:
                 raise CerbosRequestException(APIError.from_dict(resp.json()))
diff --git a/cerbos/sdk/_sync/_http.py b/cerbos/sdk/_sync/_http.py
index 5b3948a..a297dc7 100644
--- a/cerbos/sdk/_sync/_http.py
+++ b/cerbos/sdk/_sync/_http.py
@@ -196,7 +196,12 @@ def check_resources(
             resources=resources.resources,
             aux_data=aux_data,
         )
-        resp = self._http.post("/api/check/resources", json=req.to_dict())
+
+        # omit keys with `None` values
+        resp = self._http.post(
+            "/api/check/resources",
+            json={k: v for k, v in req.to_dict().items() if v is not None},
+        )
         if resp.is_error:
             if self._raise_on_error:
                 raise CerbosRequestException(APIError.from_dict(resp.json()))
@@ -265,7 +270,10 @@ def plan_resources(
             aux_data=aux_data,
         )
 
-        resp = self._http.post("/api/plan/resources", json=req.to_dict())
+        resp = self._http.post(
+            "/api/plan/resources",
+            json={k: v for k, v in req.to_dict().items() if v is not None},
+        )
         if resp.is_error:
             if self._raise_on_error:
                 raise CerbosRequestException(APIError.from_dict(resp.json()))