I have worked pretty extensively with XMPP(specially, ejabberd) in a IoT/SCADA context. Setting up your own ejabberd server is fairly painless. Download Process

I have worked pretty extensively with XMPP(specially, ejabberd) in a IoT/SCADA context. Setting up your own ejabberd server is fairly painless. Download ProcessOne's ejabberd community edition, and you should be running in an hour. Don't be afraid of erlang as you don't have to get much exposure to it unless want to. I also had the pleasure working with ProcessOne via the Business edition ejabberd support, as well as commissioning them to build few custom modules that would have taken my C++(embedded team)/C#(back-end team) centric team much more time and money to build ourselves. So ejabberd is a great way to both get your feet wet(open source community version), then scale up in a big way with professional support(commercially licensed business version) should it be needed. Note: I am not affiliated with ProcessOne in any way. Just had a pleasant experience working with them, and greatly enjoy their product.