Messaging Basics


XMPP uses JID, short for Jabber Identifier, to address and route messages to their intended recipients. A JID is composed of up to three parts: the username, the domain, and the resource.

XMPP JID as commonly seen with the username and domain only:

The domain alone can be considered a valid JID and is required. Using the domain, the client can determine what server to use. For more information about client and client library behaviors when connecting to XMPP resources, please see understanding-dns-and-xmpp.


Communicating With Other XMPP Domains (Federation)

Using XMPP it is possible to chat with users outside of your chat domain. This feature is called federation and is enabled by default on all domains. Be aware that many chat services will not accept messages from external domains until the sending user has been added to the receiving user’s roster.