Free JWT Decoder Online
Decode JWT tokens instantly. View header, payload, algorithm and expiration time securely in your browser.
Header
No data
Payload
No data
What is a JWT?
JSON Web Token (JWT) is an open standard used for securely transmitting information between parties as a JSON object. It is commonly used for authentication and authorization in modern web applications.
A JWT consists of three parts: Header, Payload, and Signature. These parts are separated by dots and encoded using Base64URL.
Why Decode a JWT?
Developers often need to inspect JWT tokens to debug authentication issues, verify expiration times, or understand claims within the payload. A JWT Decoder allows instant inspection without requiring backend tools.
Understanding JWT Structure
- Header: Contains algorithm and token type
- Payload: Contains claims and user data
- Signature: Ensures integrity
Developer Use Cases
- Debug authentication issues
- Check token expiration
- Verify claims
- Prepare interview demos
FAQ
Is this JWT Decoder secure?
Yes. All decoding happens in your browser. Your token is never stored or transmitted.
Can this verify token signature?
No. This tool only decodes header and payload. Signature verification requires the secret key.
Does this support expired tokens?
Yes. Expired tokens can still be decoded for inspection.