HandyTools Hub

πŸ” JWT Decoder

Decode and inspect JSON Web Tokens.

πŸ”’ Your data never leaves your browser

How to Use

1
### Paste your JWT token Copy your JWT token and paste it into the input field. The decoder accepts tokens in standard three-part format (header.payload.signature).
2
### View decoded header and payload The tool instantly decodes and displays the token header (algorithm, type) and payload (claims) as formatted JSON.
3
### Check expiration status See whether the token is currently valid, expired, or not yet valid based on the exp and nbf claims.
4
### Copy decoded data Select and copy the decoded header, payload, or signature for use in debugging or documentation.

Features

  • βœ“
    Decode JWT header and payload Instantly parse and pretty-print both parts of any valid JWT token.
  • βœ“
    Expiration status check Automatically checks if the token is valid, expired, or not yet active.
  • βœ“
    Algorithm detection Identifies the signing algorithm (HS256, RS256, ES256, etc.) used by the token.
  • βœ“
    Security warnings Alerts when tokens have security concerns such as expiration or algorithm issues.
  • βœ“
    Copy decoded data Easily select and copy decoded content for debugging and development.

    • Use Cases

    ### Debug authentication issues Quickly inspect JWT tokens when troubleshooting login failures, session errors, or unexpected 401 responses in your application.
    ### Inspect API tokens Decode bearer tokens from API requests to verify the claims, audience, and issuer are correctly configured.
    ### Verify token claims Check that user roles, permissions, and custom claims embedded in the token payload match expected values.
    ### Check token expiration Determine whether a token is still valid or has expired to debug unexpected logouts or token refresh failures.

    Frequently Asked Questions

    What is a JWT?

    JSON Web Token (JWT) is a compact, URL-safe token format defined by RFC 7519. It is used to securely transmit information between two parties as a JSON object. JWTs are commonly used for authentication and authorization in web applications, APIs, and microservices. A JWT consists of three parts: header, payload, and signature, separated by dots.

    Can I verify the signature?

    This tool decodes JWT tokens only and does not verify signatures. Signature verification requires the secret key (for HMAC algorithms) or the public key (for RSA/ECDSA algorithms), which should never be shared publicly. Use server-side libraries like jsonwebtoken (Node.js) or PyJWT (Python) to verify signatures securely.

    Is my token sent to a server?

    No. All decoding happens entirely in your browser using client-side JavaScript. Your JWT token is never transmitted to any server, ensuring complete privacy and security. You can safely decode tokens containing sensitive information without any risk of data leakage.