In the Jabber open-source instant messaging system, a unique identifier for a user account. Jabber IDs are formatted similarly to email addresses, reflecting the distributed nature of Jabber servers. The general format of a Jabber ID is:


The resource is used to allow one user to log in multiple times, from multiple locations or devices. Each resource's presence has a user-settable integer priority associated with it, and, when a message is sent to user@server without specifying a resource, the Jabber server forwards it to the resource whose presence has the highest priority. Multiple resources may also be used in conjunction with filters to redirect message traffic to different devices based on content or origins.

Resources may also contain parameters, in a manner similar to URIs:


These type of Jabber IDs are commonly used by Jabber transports to save login parameters for a specific service; the client subscribes to the presence of a special Jabber ID that will automatically initiate the foreign protocol connection when the user's presence is sent to that ID.