JWT Decoder

Free online JWT decoder — decode JSON Web Token headers and payloads, check token expiry, and inspect all claims without sending data to any server.

FAQ

What is a JWT?

A JSON Web Token (JWT) is a compact, URL-safe token consisting of three Base64URL-encoded parts: Header (algorithm), Payload (claims), and Signature. It is widely used for authentication and authorization.

Does this tool verify the JWT signature?

No. Signature verification requires the secret key or public key. This tool only decodes the header and payload — it cannot verify authenticity. For full verification, use jwt.io or your backend.

What claims does the decoder show?

It shows all claims in the payload, and highlights standard claims: exp (expiry), iat (issued at), sub (subject), iss (issuer), and aud (audience).

Is my JWT sent anywhere?

No. The entire decoding process runs in your browser. Your token never leaves your device.

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