About Matrix Matrix is an open protocol for decentralised, secure communications.
Matrix Manifesto We believe:
People should have full control over their own communication. People should not be locked into centralised communication silos, but instead be free to pick who they choose to host their communication without limiting who they can reach. The ability to converse securely and privately is a basic human right. Communication should be available to everyone as a free and open, unencumbered, standard and global network.
What are the differences between Matrix and Discord?
First, it’s federated, meaning that different instances of discord can talk to each other, much like Lemmy.
Second, it allows for encryption. Matrix uses the same double ratchet algorithm present in signal.
Third, joining groups is optional. This is perhaps the biggest user interface difference between discord and matrix. Each conversation exists in a independent channel, or room as they are called. Rooms can be grouped together the way you would see in discord, but they usually exist independently of the groupings. Incidentally, matrix groups are called spaces. There are edge cases where rooms are not independent from spaces, but by and large it is not something most users will have to worry about.
But you interact with other people pretty much the same way? Text/voice/video chat?
Yes. Matrix uses an integrated jitsi widget for voice and video. It is unfortunately not quite as polished as discord for voice and video, but it does work.
Element Call is in beta and works quite well. Jitsi was only used for group calls and Element Call is slowly replacing it.
Last time I tried, 3 years ago, jitsi was very much not ready. There were memory leaks, no sleep mode (one processor was fully used 100% of the time) and the video performances were bad (impossible to do a video conference with more than 3 people). How did it improved since then?
On Discord, you cannot host your own server, and you cannot use any third party clients (without the threat of being banned).
You can host your own Matrix server, either on physical hardware, or a generic virtual machine you can rent from any number of ISPs. There are over a dozen compatible third-party clients (though many lack full feature coverage).
In summary, Discord is strictly a service. Matrix is a tool you can apply however you see fit.