diff --git a/polymer.json b/polymer.json
index ac46739b4e..db6217565c 100644
--- a/polymer.json
+++ b/polymer.json
@@ -16,7 +16,7 @@
     "panels/logbook/ha-panel-logbook.html",
     "panels/map/ha-panel-map.html",
     "panels/shopping-list/ha-panel-shopping-list.html",
-    "panels/mailbox/ha-panel-mailbox.html",
+    "panels/mailbox/ha-panel-mailbox.html"
   ],
   "sources": [
     "src/**/*",