Colibri

https://colibri.social/
https://github.com/colibri-social/colibri.social

A chat client built on AT protocol, which puts all messages on the firehose, so everything is currently public.

Because Colibri is built on the AT Protocol, your community chats are public and visible to everyone by default. This open ecosystem fosters transparency, makes it easy for new members to discover your community, and ensures your data is never locked behind a walled garden.

We are closely following the protocol's development, and as soon as it supports secure private data, we will implement private spaces so you can have the best of both worlds!

They have a roadmap document here