>XMPP is uniquely well-positioned to meet these needs. It is mature, open, extensible, and governed through transparent standards. It has a community of engineers, operators, and
It's everything but mature. XMPP is a DIY flatpack plastic model kit that requires a lot of experience with super glue and paint to correctly build. As with all open source things, it is nowhere near as mature and safe as a simple Lego kit that anyone can buy and assemble in an hour.
There's a reason why this went from widely supported/used to... not so much. And even if most people claim it's big-co's locking down their ecosystems (which is partly true), the "extensibility" of XMPP allows for a very convoluted ecosystem with some servers supporting certain XEP and some not. Also, sorry, but XML just sucks to work with nowadays :(
Google’s past use of XMPP in an older iteration of its integrated Chat product (it was called Google Talk back then) is what first put this technology on my radar. In recent years I’ve been using Matrix instead — which has been covered often on HN [1].
[1] https://news.ycombinator.com/from?site=matrix.org