JWT Decoder
Free JWT decoder online — no signup required. Paste any JWT token to instantly decode and inspect the Header, Payload, and Signature. 100% client-side, your tokens never leave the browser.
Decoded JWT Token
Decoded token will appear here.
Features
- Decodes JWT header, payload, and signature separately
- Shows token expiry status — valid or expired
- Live countdown to expiry or time since expiry
- Formatted JSON with syntax highlighting
- Copy header or payload independently
- Works with any standard JWT (RS256, HS256, ES256, etc.)
Frequently Asked Questions
What is a JWT token?
JWT (JSON Web Token) is an open standard (RFC 7519) for securely transmitting information between parties as a JSON object. It consists of three Base64URL-encoded parts separated by dots: Header.Payload.Signature. JWTs are commonly used for authentication and authorization in web applications.
How do I decode a JWT token?
Paste your JWT token into the input field and the decoder instantly splits it into its three parts. The Header and Payload are Base64URL-decoded and displayed as formatted JSON. The Signature is shown as-is since it requires the secret key to verify.
Is it safe to paste my JWT token here?
Our JWT decoder works entirely in your browser — the token is never sent to any server. However, be cautious with production tokens containing sensitive user data. For maximum safety, use this tool only with test or development tokens.
What is the difference between JWT and a session token?
A session token is an opaque string stored server-side; the server must look it up in a database to verify. A JWT is self-contained — the server can verify it by checking the signature without a database lookup. JWTs are stateless and scalable but cannot be easily revoked before expiry.