How to serve my repos?

Sorry if it is, but I couldn’t find that mentioned in the doc.

How can I serve bk repos from my own server (Windows or OSX ideally)?

Is there something like freely available?

The server that you run to host your repo is called a bk bkd. That man page I linked has instructions on how to start it.

On Windows, we also have a bk service command that wraps the bkd in a Windows service so it runs is the background and restarts when you reboot.