If you've purchased a custom domain from a registrar, you can add it to your Glitch project!

To add a custom domain:

1. Within the Project Editor view, click Tools located on the lower-left side of the page.
2. Click Custom Domains.
3. Enter your custom domain URL (www.website.com) and then click Add Domain. 
4. Now, go to your domain name registrar's website and create a CNAME entry, adding glitch.edgeapp.net as the target.

Some things to remember when adding a custom domain:

• Visiting the url,  http://glitch.edgeapp.net directly in your browser will not display your app.  It’s not intended to be used directly, only as part of a CNAME.
• While you can connect a number of custom domains to your app, only the first five will appear in the custom domain menu after they have been added.
• Currently, web socket connections do not work with custom domains on Glitch. If your Glitch projects use custom domains and web sockets, you will need to set them up so that the apps are connected via their glitch.me domains.
• Most popular domain name registrars provide documentation on how to configure your dns for CNAMES. Here are links to a few of them:
  • GoDaddy
  • Name.com
  • Freenom

Using an A Record when your domain name registrar requires an IP address:

• If you want to use the "bare domain" you purchased for your custom domain (for example, website.com instead of www.website.com) most registrars won't allow that because it would break the internet (see this article for a slightly geeky but pretty understandable explanation of why).
• In this case, it's possible your registrar supports a custom DNS record type like ALIAS or A Record which will serve the same purpose.
• If not, and your registrar doesn't allow you to use a URL but instead needs an IP address, then you can get the IP address needed by pinging http:// glitch.edgeapp.net. You can use a service like Ping.eu to do so. You can then create an A record for it on your domain registrar's website.
• Here are documentation links for how to add an A record with some popular domain name registrars:
  • GoDaddy
  • Name.com
  • Freenom