Replit adds domain purchasing with instant setup and one-click configuration
Replit has launched a domain purchasing feature fully integrated into its development platform. Users now have the ability to search, buy, and configure custom domains for their apps without leaving the Replit interface, removing the need for any third-party registrar.
Domains can be found quickly through a built-in search that suggests names based on your project. With one click, users can buy a domain and have it automatically configured to point to their Replit app. The full setup from search to live site takes under a minute and supports popular extensions like .com and .ai.
This update helps users launch professional and branded apps more easily by linking domains directly to their projects. The feature is now available to all Replit users.

Comments
A number of programs do that. I think the issue is whether you can export the site from them. If your site is under a program's governance, it is likely that they hope to capitalize on yearly domain registry increases and not let users have paying ads from Google etc.