diff --git a/optimade/validator/validator_model_patches.py b/optimade/validator/validator_model_patches.py
index d0a2240ae2..ce0cda9d42 100644
--- a/optimade/validator/validator_model_patches.py
+++ b/optimade/validator/validator_model_patches.py
@@ -27,13 +27,13 @@ class ValidatorLinksResponse(Success):
 class ValidatorEntryResponseOne(Success):
     meta: ResponseMeta = Field(...)
     data: EntryResource = Field(...)
-    included: Optional[List[Dict[str, Any]]] = Field(...)
+    included: Optional[List[Dict[str, Any]]] = Field(None)
 
 
 class ValidatorEntryResponseMany(Success):
     meta: ResponseMeta = Field(...)
     data: List[EntryResource] = Field(...)
-    included: Optional[List[Dict[str, Any]]] = Field(...)
+    included: Optional[List[Dict[str, Any]]] = Field(None)
 
 
 class ValidatorReferenceResponseOne(ValidatorEntryResponseOne):