Matrix describes itself as an open standard for interoperable, de-centralised, real-time communication over IP.
Yet Another Chat Tool? Some new User-less Network Doomed to Fail? Not quite.
Matrix is federated. Which means is that – just like with email – you can setup a Matrix identity on any homeserver and then communicate with any other Matrix account on any other homeserver.
You do not need a phone number or email address to register, just a random username and a good strong password is enough.
All direct – one on one – chats are encrypted end-to-end, and chat rooms can be set so, and this includes meta data, so not even the administrator can access your data*.
* note that the IP address and time of your last connection is stored for 28 days in the database, so bad people accessing the database can get that particular bit of info.
See you on the Matrix!