diff --git a/appengine/app.yaml b/appengine/app.yaml
index 9c93fb687..563af8b24 100644
--- a/appengine/app.yaml
+++ b/appengine/app.yaml
@@ -70,6 +70,8 @@ handlers:
 # Blockly files.
 - url: /static
   static_dir: static
+  http_headers:
+    Access-Control-Allow-Origin: "*"
   secure: always
 
 # Storage API.