- Visit Developers Console.
- In your project: Compute -> App Engine -> Settings.
- On the tab labelled CUSTOM DOMAINS, you can verify your domain and assign it and/or its subdomains to your GAE project.
- Add the DNS settings provided by Google into the DNS server of your domain provider.
- Only HTTP is supported, HTTPS is not.
- It will not work if you only modify the DNS record without actually assigning the custom domain in the Developer Console.