diff --git a/foxglove_data_platform/client.py b/foxglove_data_platform/client.py
index 586b15b..02fa612 100644
--- a/foxglove_data_platform/client.py
+++ b/foxglove_data_platform/client.py
@@ -359,8 +359,8 @@ def iter_messages(
     def download_recording_data(
         self,
         *,
-        id: str = None,
-        key: str = None,
+        id: Optional[str] = None,
+        key: Optional[str] = None,
         output_format: OutputFormat = OutputFormat.mcap0,
         include_attachments: bool = False,
         callback: Optional[ProgressCallback] = None,