- Edited
Matrix is more like federated IRC with optional end-to-end encryption. It doesn't have the same privacy/security focus as Signal, but it does allow you to host your own server on your own hardware/infrastructure which you could run behind a private VPN if you wanted. IMO the reference Matrix server implementation, Synapse, seems pretty janky but it fills the niche for people who are into the whole "fediverse" thing and want an IRC/Discord alternative.