The XML-based protocol used by the Jabber open-source instant messaging system. Each message in Jabber is represented as a well-formed fragment of XML within an XML Stream. There are three primary Jabber protocol elements:

  • The <message/> element, which denotes a textual instant message being sent from one client to another
  • The <presence/> element, which allows a client to specify its presence information to the server or other clients
  • The <iq/> element, which allows a client to request or store information via the Info/Query interface

Most elements have "to=" and/or "from=" attributes, specifying the Jabber IDs of the sender and recipient, respectively. Presence and Info/Query elements also carry "id=" attributes, uniquely identifying messages and their responses.