JSON Web Token (JWT) is an open standard (RFC 7519) that defines a compact way for securely transmitting information between parties as a JSON object. It is mainly used for authorization and information exchange between different systems. It is incredibly useful for developers because it is self-contained, meaning it can be used to securely transmit information without the need to store any extra data. Furthermore, JWT is a highly secure method of authentication and authorization, as it is signed with a secret key and can be used across multiple systems. This makes it ideal for a wide range of applications, from microservices to web applications. In summary, JWT is an incredibly powerful and versatile technology that is a great choice for developers looking for secure and reliable authentication and authorization.