JWT

JSON Web Tokens (JWT) provide a compact, URL-safe means of representing claims to be transferred between two parties.

JWT is an open standard (RFC 7519) that defines a self-contained way to securely transmit information as a JSON object. It uses a three-part structure: a header (specifying the algorithm, like HS256), a payload (containing claims such as user_id: 101), and a cryptographic signature. Because these tokens are digitally signed, the receiver can verify the integrity of the data without querying a database. It is the industry go-to for stateless authentication in modern web apps and microservices.

https://jwt.io