diff --git a/vcsserver/hooks.py b/vcsserver/hooks.py
--- a/vcsserver/hooks.py
+++ b/vcsserver/hooks.py
@@ -95,9 +95,9 @@ class HooksCeleryClient:
         celery_app.config_from_object({
             'broker_url': queue, 'result_backend': backend,
             'broker_connection_retry_on_startup': True,
-            'task_serializer': 'msgpack',
+            'task_serializer': 'json',
             'accept_content': ['json', 'msgpack'],
-            'result_serializer': 'msgpack',
+            'result_serializer': 'json',
             'result_accept_content': ['json', 'msgpack']
         })
         self.celery_app = celery_app