Hi Colette,
Developers on any of our paid plans can add custom domains to their apps. Start by choosing “Publish App” from the gear menu:
In the publish dialog, choose “Share via public link”, and then “Add custom domain”
Then follow the instructions for setting up the DNS records for your domain. In particular, you will need to create a CNAME record pointing your custom domain to anvilapp.net. This is fine for subdomains like app.somewhere.com, but if you wish to use a top-level domain like somewhere.com directly, you will need to set up an A record pointing somewhere.com to our public IP address 52.56.203.177.
Once you’ve set up the DNS records, it will usually take 24-48 hours for the changes to propagate. At that point, your Anvil app will be accessible on your custom domain.
Side note: If you want to change the custom domain pointing to an Anvil app, it’s a good idea to set up the DNS records for your new domain first, and wait a day or two for the changes to propagate. Once that’s done, enter the new domain in the publish dialog as described above. This will minimise down-time for your app while the configuration switches over.
I hope that helps - let me know how you get on!