Session

A session is a unit of time during which a person engages in a coherent set of activities or an interaction with a system. In general use, sessions occur when participants are present for a planned period, such as a tutoring session, a therapy session, a recording session, or a legislative session. The term conveys continuity across a sequence of actions, ending when the activities conclude or the participants leave.

In computing, a session refers to a semi-persistent interaction between a user and an application that preserves state across multiple requests. Web applications commonly implement sessions to remember user identity and data between page loads. A session is identified by a session identifier, often stored in a cookie or token, while the server stores session data such as authentication status and user preferences. Sessions start on login or first request, may timeout after inactivity, and terminate on logout or explicit close. Proper session management involves securing session IDs, using cookies with appropriate attributes, and mitigating risks such as session fixation or hijacking.

Other contexts include database or operating system sessions, where a session represents a period of authenticated work with a resource or system. In these settings, a session may be bound to a connection, application, or user account and may be terminated when the connection ends or after a period of inactivity.

See also: session ID, timeout, cookies, and tokens.