Builder isn’t loading in Safari

If you’re using Safari and the builder isn’t loading, it’s likely that you’re running into issues with mixed content.

Safari blocks the loading of all mixed-content resources. This means that, which is loaded via HTTPS, can’t load http://localhost:3000, since it is loaded via HTTP.

The solution to this issue is to run your local Next.js app with HTTPS. If you’re not familiar with this, see our how to run your Next.js app locally with HTTPS blog post.

If you follow the instructions in the blog post, i.e., use mkcert, you might need to make sure that Node.js trusts mkcert’s CA. This can be done with the NODE_EXTRA_CA_CERTS env variable.

For example, in your package.json:

-    "dev": "next dev",
+    "dev": "NODE_EXTRA_CA_CERTS=\"$(mkcert -CAROOT)/rootCA.pem\" next dev",

If you don’t make this change you might see an UNABLE_TO_VERIFY_LEAF_SIGNATURE error. Read more in this Stack Overflow answer.

Makeswift checks if your app is running in development and will automatically bypass the SSL proxy, so you should not encounter this error unless you’re running a production build of your Next.js app or Makeswift fails to bypass the SSL proxy for some reason.

Builder isn’t loading in Brave Browser

If you’re using Brave and the builder isn’t loading, it’s likely you’re running into issues with Brave Shields and its restrictions on localhost.

Since the #463 release, Brave blocks requests to localhost from non-localhost documents.

To solve this issue, go to brave://adblock and add the following custom filter:


This prevents Brave Shields from blocking localhost requests from