diff --git a/functions/definition/user.yaml b/functions/definition/user.yaml
index da6072b..f564ad9 100644
--- a/functions/definition/user.yaml
+++ b/functions/definition/user.yaml
@@ -21,6 +21,7 @@ FbUserReadonlyType:
         optional: true
       username:
         type: string
+        optional: true  # XXX: For OSM users this is not provided
       usernameKey:
         # NOTE: web does not set usernameKey
         type: string
diff --git a/functions/generated/pyfirebase/pyfirebase_mapswipe/models.py b/functions/generated/pyfirebase/pyfirebase_mapswipe/models.py
index 72d9fd0..dc92a83 100644
--- a/functions/generated/pyfirebase/pyfirebase_mapswipe/models.py
+++ b/functions/generated/pyfirebase/pyfirebase_mapswipe/models.py
@@ -1116,7 +1116,7 @@ class FbUserReadonlyType(TypesyncModel):
         str | TypesyncUndefined | None,
         pydantic.Field(deprecated=True),
     ] = UNDEFINED
-    username: str
+    username: str | TypesyncUndefined | None = UNDEFINED
     usernameKey: str | TypesyncUndefined | None = UNDEFINED
     accessibility: bool | TypesyncUndefined | None = UNDEFINED
     userGroups: dict[str, typing.Any] | TypesyncUndefined | None = UNDEFINED
@@ -1137,6 +1137,8 @@ def __setattr__(self, name: str, value: typing.Any) -> None:
             raise ValueError("'userName' field cannot be set to None")
         if name == "userNameKey" and value is None:
             raise ValueError("'userNameKey' field cannot be set to None")
+        if name == "username" and value is None:
+            raise ValueError("'username' field cannot be set to None")
         if name == "usernameKey" and value is None:
             raise ValueError("'usernameKey' field cannot be set to None")
         if name == "accessibility" and value is None: