diff --git a/backend.py b/backend.py
index 493f8e4..cf91295 100644
--- a/backend.py
+++ b/backend.py
@@ -31,7 +31,7 @@ class EventEncoder(json.JSONEncoder):
 
 
 def dumps(data):
-    return json.dumps(data, cls=EventEncoder, sort_keys=True)
+    return json.dumps(data, cls=EventEncoder, sort_keys=True, ensure_ascii=False)
 
 
 class HeaderMiddleware: