I’m looking into hosting one of these for the first time. From my limited research, XMPP seems to win in every way, which makes me think I must be missing something. Matrix is almost always mentioned as the de-facto standard, but I rarely saw arguments why it is better than XMPP?
Xmpp seems way easier to host, requiring less resources, has many more options for clients, and is simpler and thus easier to manage and reason about when something goes wrong.
So what’s the deal?
The only things JSON has over xml is that it’s easier to write a parser for it and the format is less verbose and less complicated. There are extensions to JSON that can add features that xml has and the JSON spec doesn’t have. Overall the xml spec is bigger and has more features but that also makes it overkill for many of the cases that it would be used in.