A token is a piece of data used to authenticate a user or authorize an action in an application. Tokens allow systems to verify identity without repeatedly requesting login credentials. They are commonly used in APIs, web applications, and mobile apps. Tokens may be opaque identifiers or structured objects like JWTs. Tokens often have expiration times to enhance security. They enable stateless authentication because the server only needs to validate the token instead of storing session data.
how it works
After a user logs in, the server issues a token that represents their identity. The client stores this token, often in a cookie or header. When the client makes a request, it sends the token, and the server verifies its authenticity. Tokens may include scopes or permissions that define what the user can do. Invalid or expired tokens are rejected. Secure token management helps prevent account hijacking and unauthorized actions.