Came across this on the r/selfhosted community. Still very much in the alpha stages, but it’s already got a Docker image you can try out for yourself, or try out the demo server.
Tried it earlier today, couldn’t get the voice/video chat to work right away on my self-hosted setup but the real-time chat was very snappy. Looks promising.
Haven’t had a chance to really look into it, but there’s also spacebar chat which is an open source selfhosted reimplementation of the discord backend that can be used with existing discord clients and bots and stuff. Which depending on how solid the rest of if is, could really help existing discord people move with less effort.
Saw that earlier too, planning to check it out!