JSON Web Tokens (JWT) are a compact, URL-safe means of representing claims to be transferred between two parties. Our JWT decoder helps developers inspect and debug JWT tokens quickly and securely.

What is a JWT?

A JWT is a string consisting of three parts separated by dots: Header.Payload.Signature. The header contains the token type and hashing algorithm, the payload contains the claims (data), and the signature is used to verify the token's authenticity.

Common JWT Claims

Standard claims include iss (issuer), sub (subject), aud (audience), exp (expiration time), nbf (not before), iat (issued at), and jti (JWT ID). Custom claims can also be added to store additional information.

Security Considerations

JWTs should always be transmitted over HTTPS. Never store sensitive information in the payload as it's only base64-encoded, not encrypted. Always validate tokens on the server-side before trusting the data.

Using This Tool

Paste your JWT token in the input field and click "Decode JWT" to view the header, payload, and signature. The tool will automatically parse standard claims and display expiration information, making it easy to debug authentication issues.