Most of my current projects are a based on the Twisted Networking Framework, in Python, and often use XMPP.
- For Twisted, I maintain the Jabber/XMPP support in Twisted Words.
- Wokkel, higher level XMPP protocol support on top of Twisted Words.
- Idavoll, a generic XMPP publish-subscribe service. E.g. the Notification Server in OS X is based on this.
- Mimír, a hybrid Web-XMPP powered news service.
- python-anymeta, API support for anyMeta, including an XMPP publish-subscribe gateway with HTTP interface.