JWT Decoder

Decode JWT tokens to inspect their header, payload, and signature. View claims, check expiration status, and understand the signing algorithm — all client-side.

What is JWT Decoder?

A JWT (JSON Web Token) Decoder splits a JWT into its three parts — header, payload, and signature — and displays them in a readable format. JWTs are widely used for authentication and authorization in web APIs. This tool helps developers debug tokens without needing server-side tools.

How to Use JWT Decoder

Paste a JWT token into the input field. The tool instantly decodes and displays the header (algorithm, type), payload (claims like issuer, expiration, custom data), and signature. Color-coded sections make it easy to identify each part.

FAQ

Is it safe to paste my JWT here?

Yes, all decoding happens entirely in your browser. No data is sent to any server. However, avoid sharing JWTs publicly as they may contain sensitive claims.

Can this tool verify the signature?

No, signature verification requires the secret key (for HMAC) or public key (for RSA/ECDSA), which this client-side tool does not have access to. Use server-side libraries for verification.

What do the standard claims mean?

iss (issuer), sub (subject), aud (audience), exp (expiration time), nbf (not before), iat (issued at), and jti (JWT ID) are registered claims defined in RFC 7519.