What are JSON Web Tokens (JWT) used for?

JSON Web Tokens (JWTs) are compact and self-contained JSON payloads that contain all the necessary data to authenticate users, negating the need for constant database calls every time you want to verify a user's details. JWTs consist of three parts: header, payload, and signature. They secure data using a digital signature and can be used in various applications such as authentication, authorization, and information exchange between different systems. The benefits of using JWTs include simplicity, scalability, high customizability, and cross-domain support. However, they may not be the best option if your app highly prioritizes security or frequently revokes user access. Implementing JWT authentication in a Node.js project can be done using the jsonwebtoken package.