A few months ago, I announced a service for managing Go import paths for custom domains gopherpit.com. It was made for personal needs for private and commercial projects that are not hosted on github. The source code and binary releases are now available on GitHub, as well as docker image. It has all the same features as the one hosted on gopherpit.com. Some may just need a publicly available service, while other prefer to manage it privately. I hope that you find it useful.