JWTio

JWT.io is a popular online tool and library for working with JSON Web Tokens (JWTs). JWTs are a compact, URL-safe means of representing claims to be transferred between two parties. The claims in a JWT are encoded as a JSON object that is used as the payload of a JSON Web Signature (JWS) structure or as the plaintext of a JSON Web Encryption (JWE) structure, enabling the claims to be digitally signed or integrity protected with a Message Authentication Code (MAC) and/or encrypted.

JWT.io provides a user-friendly interface for creating, verifying, and decoding JWTs. Users can input the header, payload, and secret to generate a JWT, or input an existing JWT to decode and verify it. The tool supports various algorithms for signing and verifying JWTs, including HMAC, RSA, and ECDSA.

The library aspect of JWT.io is a collection of open-source libraries for different programming languages, such as JavaScript, Python, Java, and Ruby. These libraries allow developers to integrate JWT functionality into their applications easily. The libraries provide methods for encoding and decoding JWTs, verifying signatures, and handling different algorithms.

JWT.io is widely used in web development for implementing authentication and authorization mechanisms. It is particularly useful for single sign-on (SSO) systems, where a user's identity is verified once and then granted access to multiple applications without re-entering login credentials. The tool and library are maintained by Auth0, a company specializing in identity and access management solutions.