Even with a binary format, you'd be sending data out of band in XMPP. XMPP is designed for interchanging _small_ bits of data. Having implemented both XMPP cli

Even with a binary format, you'd be sending data out of band in XMPP. XMPP is designed for interchanging _small_ bits of data. Having implemented both XMPP clients and servers, I don't particularly see your point. Exchanging small binary message packets would not be an issue. How would binary stanzas be any different than other message-based multiplexing binary protocols?. Also, the complexity of out-of-band protocols in XMPP has nothing at all to do with XML. The fact that you have to go OOB at all introduces significant complexity.