I am searching an open source alternative to Slack.
- modern chat solution (public, private rooms, discussion threads, emoji-reactions, notification about unread messages, search, …)
- client needs to be open source
- server needs to be open source
- self-hosting should be possible
- A web-based GUI should be available
- Mobile usable web GUI (or native app).
- Most features of the software should be accessible via keyboard (without mouse).