diff --git a/src/waylay/sdk/api/serialization.py b/src/waylay/sdk/api/serialization.py
index 2856d61..fa8097b 100644
--- a/src/waylay/sdk/api/serialization.py
+++ b/src/waylay/sdk/api/serialization.py
@@ -60,7 +60,7 @@ def build_request(
         resource_path: str,
         path_params: Optional[Mapping[str, str]] = None,
         *,
-        params: Optional[Union[QueryParamTypes, Mapping]] = None,
+        params: Optional[Union[QueryParamTypes, Mapping, BaseModel]] = None,
         json: Optional[Any] = None,
         content: Optional[RequestContent] = None,
         files: Optional[RequestFiles] = None,