How to do Custom Domains with Fly

We’ve just published Custom Domains with Fly, the latest of our application guides which shows how you can use Fly to proxy traffic or serve applications for multiple custom domains.

In Custom Domains with Fly, you’ll learn how to configure an NGINX server to proxy traffic to external sites and how to attach host and domain names to your Fly applications using Fly’s command line flyctl.

For those of you who practice devops and automate everything, the article also has details on the Fly GraphQL API for adding, removing, checking and deleting hosts and associated certificates. There’s also a repository of ready-rolled Node applications which clearly demonstrate how the API works and offer a jumping off point for any developer looking to customize their Fly experience.


For a taste of how straightforward the process can be, here’s a speed run for adding a host/domain to an application. Let’s say we have and a Fly app called custom-quartz.

  • Run flyctl ips list -a custom-quartz to get the IPv4 and IPv6 addresses.
  • Head over to your DNS provider and add A and AAAA records for with the IPv4 and IPv6 values.
  • Run flyctl certs create -a custom-quartz
  • Run flyctl certs show -a custom-quartz to watch your certificates being issued.
  • Connect to and use your application with auto-renewing Let’s Encrypt TLS certificates, edge TLS, HTTP/2 support and more.

For Proxies, For All

There’s no limit to the number of certificates you can attach to an Fly application. That means that if you’re in the business of producing branded applications with custom domains, Fly is a great place to unify all your proxying needs into one globally fast application which scales on demand.

Fly your own flag on your Fly applications today.

Want to learn more about Fly? Head over to our Fly Docs for lots more, including a Hands On where you can get a free account and deploy your first app today.