JWT Decoder — decode JWT online

JSON Web Token (JWT) is a compact format for transferring claims between parties. A token consists of three Base64url-encoded parts separated by dots: Header, Payload, and Signature.

JWT Structure

• Header — token type and signing algorithm (alg, typ);
• Payload — claims: user data and metadata (iss, sub, exp, iat, etc.);
• Signature — HMAC or RSA/ECDSA signature for token verification.

Standard Claims (RFC 7519)

• iss — Issuer: who issued the token;
• sub — Subject: who the token was issued to;
• aud — Audience: intended recipient;
• exp — Expiration Time: token expiry (Unix timestamp);
• nbf — Not Before: token is not valid before this time;
• iat — Issued At: time the token was issued.