GDPR session timeout enforcement is not optional. Under Article 5(1)(e), personal data must not be stored longer than necessary. That applies to active user sessions as much as to databases. If a session doesn’t expire when it should, you risk a direct violation, potential fines, and a security gap for attackers to exploit.
A compliant session timeout policy starts with defining a strict inactivity threshold. Many organizations set this between 5 and 15 minutes for systems handling personal or sensitive data. The timeout must be enforced server-side, not just in client code, to prevent bypass through disabled scripts or manipulated browsers. Store the last activity timestamp securely on the server, check it on every request, and terminate the session token once the limit is reached.
Session invalidation must be immediate. That means deleting the session record in your store—whether it’s a database, memory cache, or distributed session manager—and ensuring any cached authentication data is purged. Token-based authentication systems, like JWT, require special handling: you cannot revoke an unexpired token without a server-side blacklist or short token lifespan combined with refresh token rotation.