JSON Web Tokens (JWT) are an open standard (RFC 7519) for securely transmitting information between parties as a JSON object. A JWT consists of three parts separated by dots: Header, Payload, and Signature. This tool decodes the header and payload without verifying the signature. Your tokens are processed entirely in your browser and never sent to any server.
JWT (JSON Web Token) is a compact, URL-safe way to transmit claims between parties. It has three parts: Header, Payload, and Signature — each Base64-encoded and separated by dots.
Our tool decodes the header and payload for inspection, but does not verify the cryptographic signature. For verification, you need the secret key or public key, which should remain private.
Yes, all decoding happens in your browser. Your JWT tokens are never sent to any server. However, only decode tokens on trusted devices and never share tokens that contain sensitive claims.
JWTs often carry user identity claims (sub, email, name). Avoid storing sensitive information in JWT payloads because the payload is only Base64-encoded (not encrypted) and can be read by anyone with the token.