JJ should be compatible with any existing Git server. The project is currently maintained on Github, and I believe all the maintainers use JJ to work on the project itself. At work, I use JJ a lot with repositories hosted on Azure Devops, and that also works well (in some ways, better than Github).
This is using JJ's "Git" backend, which internally stores data as Git refs, and communicates with other servers the same way that Git does. There is a work-in-progress native backend, but this is still being developed and you need to explicitly opt into it if you want to try it out.
This is using JJ's "Git" backend, which internally stores data as Git refs, and communicates with other servers the same way that Git does. There is a work-in-progress native backend, but this is still being developed and you need to explicitly opt into it if you want to try it out.