diff --git a/deluge/ui/web/json_api.py b/deluge/ui/web/json_api.py
index f11cf3d53..2ea0e493c 100644
--- a/deluge/ui/web/json_api.py
+++ b/deluge/ui/web/json_api.py
@@ -230,7 +230,7 @@ class JSON(resource.Resource, component.Component):
         if request._disconnected:
             return ''
         response = json.dumps(response)
-        request.setHeader(b'content-type', b'application/x-json')
+        request.setHeader(b'content-type', b'application/json')
         request.write(compress(response.encode(), request))
         request.finish()
         return server.NOT_DONE_YET