I've just released PubSub Chat, a "toy" chat system that only relies on Redis-compatible / PubSub-enabled database (and no other server app)
https://codeberg.org/brunobord/pubsub-chat
I've tried to document it the best I could ; don't forget that it's quite unsafe and is NOT meant to replace IRC, Matrix, XMPP, etc.
But that was fun reviving it.

