logout

Logout is the process of ending an authenticated session with a computer system or online service. It terminates access rights granted during a login and prevents continued use of the account from the current device.

In web applications, logout typically invalidates the server-side session by destroying session data and clearing client-side authentication data such as cookies or tokens. The user is usually redirected to a login screen or a public page. In token-based systems, logout may involve revoking access and refresh tokens to prevent re-use.

Logout can be manual, where the user explicitly signs out, or automatic, triggered by inactivity timeouts or other security policies. For services that use single sign-on, logout may involve the identity provider to terminate access across linked applications, potentially ending sessions on multiple platforms.

Security considerations are central to logout behavior. Proper logout should revoke all active tokens and clear cookies with appropriate attributes (such as HttpOnly, Secure, and SameSite). Systems should address risks like cross-site request forgery and session fixation, and may require re-authentication for sensitive operations. Logging out from all devices helps prevent unauthorized use if a device is lost or stolen.

Limitations exist, as some services maintain persistent sessions or remember devices. Users on shared or public devices should always log out after use and review active sessions in account settings to terminate any remaining sessions. Regularly updating credentials and using multi-factor authentication can further reduce risk.