Other people provided some info:

https://news.ycombinator.com/item?id=9772968

https://news.ycombinator.com/item?id=31133082 (article and discussion)

But TL;DR:

* It's hard to even parse, XMPP uses an uninterrupted XML stream. * The contents are often baroque and complex * Standards are a mess, and stuff that should be in core isn't * Data loss is possible * Protocol wasn't made for mobile devices * Multiple devices are terribly supported * Data loss is possible

From my attempts long ago, and other testimonials, writing an XMPP client is a full time job of solving weird problems that shouldn't exist in something better designed.

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fishgoesblub 6 hours ago | parent [-]

Regarding the part part: https://www.process-one.net/blog/stop-telling-us-xmpp-should...

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p2detar 5 hours ago | parent | next [-]

> We hear this too often: “XMPP uses XML. It should use JSON—it’s more modern.”

I can't take this write-up seriously if it starts like that. I still read the whole thing though and I couldn't find any solid argument as to why someone would prefer XML to JSON for XMPP.

> This is especially true in browser environments, where XMPP streams run over WebSockets, which naturally frames the XMPP protocol. That’s why you are never actually working with XML trees consuming large chunks of memory. Modern implementations like XMPP.js go further and use LTX—a lightweight parser built specifically for XMPP’s streaming model—rather than the browser’s DOM parser. The result: developers work with JSON-like objects anyway. The wire format becomes invisible to your application code.

That to me, is an argument for using JSON, not XML. XML is strong when you have elements referencing other elements in your document structure or DOCTYPE for grammar defs. I might be missing something but I don't get how streaming XML is to be preferred over JSON for XMPP.

	▲	Dylan16807 2 hours ago \| parent [-]
		If it was actually using XML as a markup language then that would be a reason to stick with it. But XML seems to be complicating things much more than it simplifies. >> XML remains the best format for representing trees—deep hierarchies of nested data. JSON handles flatter structures well, but good messaging protocols are extensible: extensions can be embedded at different levels and composed together, like Lego bricks. That’s where XML shines. Anything reasonable you'd be doing with messaging protocol is pretty flat.

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5 hours ago | parent | prev | next [-]

[deleted]

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dale_glass 6 hours ago | parent | prev [-]

What part part, sorry?