Extensible Messaging and Presence Protocol, or XMPP, is an open, XML-based protocol for near real-time extensible messaging and presence events. It is the core protocol of the Jabber Instant Messaging and Presence technology which is currently deployed on thousands of Jabber servers across the Internet and is used by millions of people worldwide. The IETF XMPP working group aims to adapt the XMPP for use as an IETF Instant Messaging and presence technology.

Specifications

The IETF XMPP working group has produced a number of RFCs:

• RFC 3920, Extensible Messaging and Presence Protocol (XMPP): Core which describes client-server messaging using two open ended XML streams. XML streams consist of <presence/>, <message/> and <iq/> (info/query) as illustrated in the example client-server conversation. A connection is authenticated with Simple Authentication and Security Layer (SASL) and encrypted with Transport Layer Security (TLS).
• RFC 3921, Extensible Messaging and Presence Protocol (XMPP): Instant Messaging and Presence describes instant messaging (IM), the most common application of XMPP.
• RFC 3922, Mapping the Extensible Messaging and Presence Protocol (XMPP) to Common Presence and Instant Messaging (CPIM) relates XMPP and the Common Presence and Instant Messaging (CPIM) specifications.
• RFC 3923, End-to-End Signing and Object Encryption for the Extensible Messaging and Presence Protocol (XMPP) describes end to end encryption of XMPP messages using S/MIME. Conflicting this proposal, many clients currently use GPG for encrypting messages.

Implementations

• XMPP is implemented by the numerous Jabber clients and servers
• Twisted Matrix Labs' Twisted (a Python based framework for writing networked applications) supports XMPP.

External links

• Official press release from the JSF regarding the publication of the official RFC numbers.
• XMPP working group