What are the Differences Between the gtsb.io and gatsbyjs.io Domains?

gtsb.io

The gtsb.io domain is used for previewing changes and is not intended for production use. CMS Preview, PR builds, and Production Build previews all use the gtsb.io domain, ex:

gatsbyjs.io

The gatsbyjs.io domains are production-quality domains that are behind a CDN. These can be used in a staging/development environment, and provide a way to preview the performance of Gatsby Cloud Hosting before adding a custom domain.