diff --git a/etebase_server/fastapi/routers/collection.py b/etebase_server/fastapi/routers/collection.py
index 9fe74f1..2de35a8 100644
--- a/etebase_server/fastapi/routers/collection.py
+++ b/etebase_server/fastapi/routers/collection.py
@@ -152,7 +152,7 @@ class CollectionItemRevisionListResponse(BaseModel):
 
 class CollectionItemBulkGetIn(BaseModel):
     uid: str
-    etag: t.Optional[str]
+    etag: t.Optional[str] = None
 
 
 class ItemDepIn(BaseModel):