JID

JID stands for Jabber ID, the addressing identifier used in the Extensible Messaging and Presence Protocol (XMPP) to identify entities on an XMPP network. It is used to route messages, presence information, and other stanzas between clients, servers, and components. A JID uniquely identifies a connection or account on the network and can refer to a user, a server, or a specific resource associated with a user.

A JID has three potential parts: localpart, domainpart, and resourcepart. The localpart (often a username) is placed before the at-sign, the domainpart (the server’s domain) follows the at-sign, and the resourcepart, which identifies a particular session or connection, appears after a slash. Bare JIDs omit the resourcepart, while full JIDs include all three parts. Example forms include [email protected], [email protected]/home, and example.org (domain JID, often used to refer to a server or component).

Usage-wise, JIDs are used to route messages, presence updates, and other XMPP stanzas. A single user may have multiple resources (for example, a desktop client and a mobile client), each with its own resourcepart. Presence information can be exposed per resource, and servers may route communications based on the bare JID or a full JID depending on the context and privacy settings.

Historically, the Jabber project (launched in the late 1990s) evolved into XMPP, an open standard standardized by the IETF. The term JID remains the practical address form used by clients and servers to identify and communicate with entities on the network.