Online JWT decoder and verifier — parse Header/Payload/Signature, verify HS256 signatures, check expiry. Fully local.
❓ FAQ
What is a JWT?
JWT (JSON Web Token) is an open standard (RFC 7519) for securely transmitting JSON-based claims between parties. It is widely used for authentication and authorization.
What are the three parts of a JWT?
A JWT consists of Header, Payload, and Signature, separated by dots. Each part is Base64URL-encoded.
What is the difference between HS256 and RS256?
HS256 uses a symmetric key (same key for signing and verification), while RS256 uses an asymmetric key pair (private key to sign, public key to verify). This tool supports HS256/HS384/HS512.
Is it safe to decode JWTs here?
This tool runs entirely in your browser. Your token and secret are never sent to any server.