A JWT JSON Web Token is widely used for authentication, session handling and secure API communication. When working with authorised systems, being able to decode a token helps you view its payload, understand claims and debug issues during development.
This JWT Decoder lets you paste or upload a token to reveal the header, payload and signature components. It works entirely client side so nothing you decode is stored or transmitted to a server. This tool is ideal for developers who need to inspect token contents quickly and safely.
Header
Payload
JWTs are formatted in three parts separated by dots. The header contains the algorithm and token type, the payload holds claims such as user ID or expiry time, and the signature verifies authenticity. Being able to decode and inspect these values makes it easier to troubleshoot authentication flows, verify token expiry and confirm data sent within a request.
Parts of a JWT
| Section | Description |
|---|---|
| Header | Defines token type and signing algorithm |
| Payload | Contains claims and data related to the user or session |
| Signature | Ensures the token has not been modified or tampered with |
Use this JWT Decoder for testing, API verification, debugging login systems or learning how token based authentication works. It is a simple and secure way to view JWT content without risking exposure of sensitive information to external servers.