JWT Decoder

Professional JWT token debugger with advanced features and security validation

Encoded JWT Token

Security Warning

This tool runs entirely in your browser. No tokens are sent to our servers. However, be cautious with production tokens containing sensitive data.

Signature Verification

Header

🔐

Header will appear here when you paste a valid JWT token

Payload

📋

Payload will appear here when you paste a valid JWT token

Token Info

ℹ️

Token information will appear here when you paste a valid JWT token

About JWT Tokens

JSON Web Tokens (JWT) are a compact, URL-safe means of representing claims to be transferred between two parties. The claims in a JWT are encoded as a JSON object that is used as the payload of a JSON Web Signature (JWS) structure or as the plaintext of a JSON Web Encryption (JWE) structure, enabling the claims to be digitally signed or integrity protected with a Message Authentication Code (MAC) and/or encrypted.

How to Use Advance JWT Decoder

Step-by-step guide to effectively utilize the Advance Jwt Decoder.

1

Paste Your JWT Token

Copy your JWT token from your app, API, or browser storage and paste it into the input box. The tool will automatically detect the three parts of the token — header, payload, and signature.

eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiaWF0IjoxNTE2MjM5MDIyfQ.SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c
2

View Decoded Header and Payload

The tool quickly decodes your token and shows the header (algorithm and type) and payload (user data and claims) in an easy-to-read JSON format.

Header: {"alg": "HS256", "typ": "JWT"} Payload: {"sub": "1234567890", "name": "John Doe", "iat": 1516239022}
3

Select Algorithm Type

Choose the correct algorithm used for your token — HS256, HS384, HS512, RS256, RS384, or RS512. This helps decode and verify the token properly.

const jwt=require('jsonwebtoken');const decoded=jwt.verify('your.jwt.token','your-256-bit-secret',{algorithms:['HS256']});console.log(decoded);
4

Verify Token Signature (Optional)

If you want to check if the token is real, enter your secret key (for HMAC) or public key (for RSA). The tool will tell you if the token is valid

Secret Key: your-256-bit-secret Signature Status: ✓ Valid
5

Copy or Analyze Token Data

Once decoded, you can copy the header, payload, or full token info for debugging, API testing, or documentation.

navigator.clipboard.writeText(JSON.stringify(decoded, null, 2)); // Copy decoded JWT data

💡 Pro Tip

Use a representative sample that includes all possible fields.

Advanced JWT Decoder Use Cases

Discover how developers across different domains use our Advanced Jwt Decoder Tool.

Backend Developers

  • Debug authentication issues in API requests or middleware
  • Verify JWT tokens received from frontend apps
  • Check the payload and custom claims inside tokens
  • Find token expiration or timing problems quickly
  • Validate signatures using different algorithms like HS256 or RS256.

Frontend Developers

  • Inspect login tokens saved in browser storage
  • Debug OAuth or single sign-on (SSO) login flows
  • Verify user roles and permissions from decoded claims
  • Test token-based login systems during app development
  • Understand token data for better client-side handling.

Security Professionals

  • Review and test JWT security setup in web applications
  • Analyze tokens to detect tampering or unusual data
  • Confirm signature algorithms and secret key strength
  • Check for common JWT weaknesses or misconfigurations
  • Investigate suspicious tokens or authentication bypass attempts.

🚀 Why Use This Tool?

Save hours of manual work, reduce errors, and ensure consistency.

FAQ

Frequently Asked Questions

Get answers to common questions about the Laravel Migration & Model Generator tool.

A JWT (JSON Web Token) is a small piece of data used to check who a user is. When you log in, the system gives you a token. Every time you make a request, the token proves your identity without needing to log in again.

Our tool supports popular algorithms like HS256, HS384, HS512, RS256, RS384, and RS512. These are used to sign and check tokens safely.

Yes, it’s safe. The tool works directly in your browser, so your token data never goes to any server or gets saved.

Yes. You can add a secret key to verify the token signature and check if someone changed or tampered with the token.

You can see the header, payload, and signature. This includes user info, token type, algorithm used, and token expiry details.

You can use the tool to decode and check if the token is expired, signed with the right key, or formatted correctly. This helps find and fix login or authentication errors easily.

Yes, you can use the “Show Secret” option to enter a secret key and verify your token’s authenticity.

Absolutely! The JWT Decoder is 100% free and part of UIBuilderHub’s collection of 45+ online tools for developers.