Free JWT Decoder Online - Decode & Verify Tokens
Decode and inspect JSON Web Tokens. View header, payload, and signature instantly.
Example data loaded — edit or paste your own JSON below.
JWT Decoder: Complete Guide
What is JWT?
JSON Web Token (JWT) is an open standard for securely transmitting information between parties. JWTs are commonly used for authentication and authorization in web applications.
JWT Structure
A JWT has three parts separated by dots:
- Header - Contains algorithm and token type
- Payload - Contains claims (user data)
- Signature - Verifies token authenticity
Common Claims
| iss | Issuer |
| sub | Subject (usually user ID) |
| aud | Audience |
| exp | Expiration time |
| iat | Issued at time |
Related Tools
How to Use This Free Online JWT Decoder Tool
Our free online JWT decoder makes it simple to decode and inspect JSON Web Tokens directly in your browser. Whether you're debugging authentication issues, verifying token claims, or learning how JWT tokens work, this online JWT decoder tool provides instant results with no server-side processing—your tokens never leave your device.
Step-by-Step JWT Decoding Guide
- Copy your JWT token from your application's authorization header or cookie.
- Paste the token into the input field above. A valid JWT consists of three Base64URL-encoded parts separated by dots.
- Click Decode JWT to instantly inspect the header, payload, and signature sections.
- Review the decoded claims: check the
exp(expiration),iat(issued at), andsub(subject) fields.
Code Example: Manual JWT Decoding
// Decode JWT payload in JavaScript
const jwt = "eyJhbGciOiJIUzI1NiJ9.eyJzdWIiOiIxMjM0In0.xxx";
const parts = jwt.split('.');
const payload = JSON.parse(atob(parts[1]));
console.log(payload.sub); // "1234"
console.log(payload.exp); // Check expirationThis free online JWT decoder supports all common algorithms including HS256, RS256, and ES256. For a complete JWT debugging guide, check our related articles below. Remember: decoding only reads the token—always verify signatures server-side for security.