What is a Stateless service and how does it work (using JWT tokens as an example)?

Stateless service is a service that does not store state between client requests. Each request contains all the necessary information for processing, and the server does not depend on previous interactions.

Using JWT (JSON Web Token) as an example, it works as follows:

• During authentication, the user receives a JWT that contains encoded information (e.g., user_id, expiration time, access rights).
• The client sends this token in the header (usually Authorization) with each request.
• The server verifies the token's signature and extracts data without accessing a database or sessions.
• If the token is valid, the server processes the request without maintaining user state between requests.

Thus, the server does not store session data, which simplifies scaling and increases fault tolerance.