(#pvohbma) @prologic@twtxt.net I’m not sure, but this is the best I found on a quick search: PeerChat, if I remember correctly OwnCloud offer a chat plugin which is self hosted too.

Fun fact: I thought of making an app like that for fun just two days ago while chatting with a friend, never started since I didn’t really needed and was more of a toy project though. 😄