Online JWT Decoder - Decode JWT Tokens

Free and secure online tool to decode JWT (JSON Web Tokens). View header, payload and signature directly in your browser. Perfect for developers, API testing and authentication debugging.

Decode JWT Token

A JWT token consists of 3 parts separated by dots: header.payload.signature

Understanding JWT Claims

Registered Claims (RFC 7519):

iss Issuer - Token issuer
sub Subject - Subject (User ID)
aud Audience - Target audience
exp Expiration - Expiration time
iat Issued At - Issued at time
nbf Not Before - Valid from time

Main Use Cases:

  • User authentication
    Secure login for web and mobile applications
  • Access authorization
    Permission control and protected resources
  • Single Sign-On (SSO)
    Single access across multiple applications
  • Stateless APIs
    Secure communication between services
  • Microservices
    Distributed and scalable authentication

Supported Signing Algorithms

Symmetric (HMAC):

HS256 HMAC SHA-256

Most common, shared secret key

HS384 HMAC SHA-384

Higher security, longer hash

HS512 HMAC SHA-512

Maximum HMAC security

Asymmetric (RSA/ECDSA):

RS256 RSA SHA-256

Public/private keys, ideal for distribution

ES256 ECDSA SHA-256

Elliptic curves, superior performance

PS256 RSA PSS SHA-256

RSA with probabilistic padding

Frequently Asked Questions about JWT

What is a JWT (JSON Web Token)?

JWT (JSON Web Token) is an open standard (RFC 7519) that defines a compact and self-contained way to securely transmit information between parties as a JSON object. It's widely used for authentication and authorization in modern web applications.

Is it safe to decode JWT online?

Yes! Our tool processes everything locally in your browser. No tokens are sent to our servers, ensuring complete privacy and security of your sensitive data.

What's the difference between header, payload and signature?

Header: contains metadata about the token (signing algorithm, type). Payload: contains user information (claims) and token data. Signature: ensures the token hasn't been altered and verifies authenticity.

Can I validate the JWT signature with this tool?

This tool decodes and displays JWT content, but doesn't validate the signature (which requires the secret key). For complete validation, use JWT libraries in your development environment with the appropriate key.

How to check if a JWT has expired?

Check the "exp" (expiration) field in the payload. This value is a Unix timestamp. Compare it with the current timestamp to determine if the token has expired. Expired tokens should be rejected by the application.

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