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Changing Your Heroku App Name

Overview

If you rename your Heroku app (for example, from my-app to my-new-app), the WAF’s backend connection will break. This is because the WAF routes traffic to your Heroku app using its .herokuapp.com hostname, and renaming the app changes that hostname.

Note: If you are changing your external domain (e.g., old.example.com to new.example.com), see Changing Your Domain instead — that is a different process.

Why This Happens

The WAF proxies traffic to your Heroku app using the .herokuapp.com URL as the origin server:

Visitor → WAF → my-app.herokuapp.com → Your App

When you rename your Heroku app, the .herokuapp.com URL changes:

Old: my-app.herokuapp.com New: my-new-app.herokuapp.com

The WAF will still be pointed at the old URL, which no longer exists. This causes the WAF to return errors because it cannot reach the origin server.

What to Do

You have two options for updating the WAF’s origin after renaming your Heroku app:

Option 1: Schedule a call with us — We’re happy to get on a call and do the migration for you.

Option 2: Use the API — You can script the change yourself using the Origins API endpoint to update the WAF’s origin to your new .herokuapp.com hostname.

Either way, we’ll need:

  • Your old Heroku app name
  • Your new Heroku app name
  • The domain associated with your WAF

Your custom domain, DNS settings, SSL certificate, and WAF rules are not affected by a Heroku app rename — only the backend origin needs to be updated.

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