🔑 JWT Decoder

Parse and verify JSON Web Tokens, view Header, Payload, and Signature information

⚠️ Warning: Do not input real production tokens in this tool! All data is processed locally in the browser, but for security, only use test tokens.

JWT Token

📚 Example Tokens

💡 Common Fields

alg: Algorithm

typ: Type

iss: Issuer

sub: Subject

aud: Audience

exp: Expiration

nbf: Not Before

iat: Issued At

jti: JWT ID

FAQ

What is JWT?

JWT (JSON Web Token) is an open standard (RFC 7519) for securely transmitting information between parties. It consists of three parts: Header, Payload, and Signature.

Is JWT secure?

JWT is secure when used correctly: 1) Use strong signing keys; 2) Set reasonable expiration times; 3) Transmit over HTTPS; 4) Don't store sensitive info in Payload (it's Base64 encoded, not encrypted).

What is the difference between JWT and Session?

JWT is stateless - servers don't need to store session info, suitable for distributed systems. Sessions are stateful, requiring server storage but easier to revoke. Choice depends on your use case.

How to verify JWT signature?

Our tool only decodes JWT, not verifying signatures (requires secret key). In production, use backend libraries (like jsonwebtoken) to verify signatures and ensure tokens haven't been tampered with.