diff --git a/src/simdb/remote/models.py b/src/simdb/remote/models.py
index 0a8218c..d8d2d2d 100644
--- a/src/simdb/remote/models.py
+++ b/src/simdb/remote/models.py
@@ -352,7 +352,7 @@ class SimulationListItem(BaseModel):
     """Alias of the simulation."""
     datetime: str
     """Creation timestamp."""
-    metadata: Optional[MetadataDataList] = None
+    metadata: MetadataDataList = MetadataDataList()
     """Simulation metadata."""