What is a JWT Decoder & Inspector?
A JWT (JSON Web Token) is a compact, URL-safe token format used for authentication and authorization in web applications. It consists of three Base64URL-encoded parts separated by dots: the header (algorithm and token type), the payload (claims about the user or session), and the signature. PureFormatter's JWT decoder decodes the header and payload and displays them as readable JSON, highlights expiry timestamps, and warns if the token has expired.