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.
Depends on the usecase. If you don’t need chat history for new-joiners, you can work with a single key per group, rotating it whenever someone joins or leaves. Since the server broadcasts a „so-and-so has left/joined“ it might as well include the new key. That key is then used by everyone in the group, so you can still broadcast all messages and don’t have to encrypt them individually.