We’ve been exploring ways to use Fastly to supercharge your Glitch websites, and use Glitch to help people learn and onboard with Fastly! 
We have a new Glitch app and tutorial that takes you through setting up a Fastly CDN service for your site, and pointing your own domain at it with free Fastly TLS. Using the CDN gives your site a performance boost beyond what you can achieve with Glitch alone, and of course we know how important it is to be able to use your own domains with your Glitch projects.
You can follow the steps in the Fastly docs, or in the Glitch project, by remixing it and referring to the README:
I shared a little more about this work over on the blog:
The Glitch project also shows you how to find information about your site behavior and performance using browser tools. Over the next few months we’ll be sharing a similar learning experience for those who want to know more about edge computing…!