diff --git a/api/controllers/service_api/app/completion.py b/api/controllers/service_api/app/completion.py
index c8674356d1..509fb38cd7 100644
--- a/api/controllers/service_api/app/completion.py
+++ b/api/controllers/service_api/app/completion.py
@@ -31,7 +31,7 @@ class CompletionApi(AppApiResource):
         parser.add_argument('query', type=str, location='json', default='')
         parser.add_argument('files', type=list, required=False, location='json')
         parser.add_argument('response_mode', type=str, choices=['blocking', 'streaming'], location='json')
-        parser.add_argument('user', type=str, location='json')
+        parser.add_argument('user', required=True, nullable=False, type=str, location='json')
         parser.add_argument('retriever_from', type=str, required=False, default='dev', location='json')
 
         args = parser.parse_args()
@@ -96,7 +96,7 @@ class ChatApi(AppApiResource):
         parser.add_argument('files', type=list, required=False, location='json')
         parser.add_argument('response_mode', type=str, choices=['blocking', 'streaming'], location='json')
         parser.add_argument('conversation_id', type=uuid_value, location='json')
-        parser.add_argument('user', type=str, location='json')
+        parser.add_argument('user', type=str, required=True, nullable=False, location='json')
         parser.add_argument('retriever_from', type=str, required=False, default='dev', location='json')
         parser.add_argument('auto_generate_name', type=bool, required=False, default=True, location='json')