JWT, or JSON Web Token, is a compact and self-contained way to securely transmit information between parties as a JSON object. It is commonly used for authentication and information exchange in web applications. A JWT consists of three parts: a header, a payload, and a signature, which together ensure the integrity and authenticity of the data. The header typically specifies the type of token and the signing algorithm used. The payload contains the claims or information about the user, while the signature is created by combining the encoded header, payload, and a secret key. This structure allows JWTs to be easily verified and trusted by the receiving party.