JWT Decoder
Decode and inspect any JWT (JSON Web Token) instantly. View the header, payload, and expiry status. Client-side — your token stays private.
Frequently asked
questions
Yes — decoding happens entirely in your browser. Your token is never sent to any server. That said, never share JWTs from production systems with anyone; treat them like passwords.
No. Decoding only reads the Base64-encoded payload — it does not verify the cryptographic signature. Signature verification requires the secret key, which should never leave your server. Use server-side libraries (jsonwebtoken, PyJWT, etc.) to verify.
A JSON Web Token (JWT) is a compact, URL-safe token format used for authentication and information exchange. It consists of three Base64URL-encoded parts separated by dots: Header.Payload.Signature. The header and payload are readable by anyone; only the signature proves authenticity.