diff --git a/rossum_api/models/user.py b/rossum_api/models/user.py
index 263831b..a37cec7 100644
--- a/rossum_api/models/user.py
+++ b/rossum_api/models/user.py
@@ -14,7 +14,7 @@ class User:
     date_joined: str
     username: str
     organization: str
-    last_login: str
+    last_login: Optional[str] = None
     is_active: bool = True
     email_verified: Optional[bool] = False
     password: Optional[str] = None