JWT, or JSON Web Token, is a compact and self-contained way to securely transmit information between parties as a JSON object. In its essential form, it consists of three parts: a header, a payload, and a signature.The header typically indicates the token type and the signing algorithm used. The payload contains the claims, which are statements about an entity (usually the user) and additional data. Claims can be registered, public, or private, depending on the use case. The signature is created by taking the encoded header and payload, combining them, and signing the resulting string with a secret or a public/private key pair. This helps ensure that the token is not altered during transmission and can be verified by the receiving party.JWTs are useful for authentication and information exchange. They enable users to prove their identity securely while minimizing the need to share sensitive data repeatedly. Many systems use JWTs, making them a popular choice for APIs and web applications.