JWT Inspector
Offline JSON Web Token decoder. Your token and secret never leave the browser. 100% Client-Side.
Capabilities
Decodes JWT header and payload instantly, and verifies HS256 signatures locally using the browser's native SubtleCrypto API.
Target Use Cases
- Debugging authentication token structures
- Verifying signature integrity for local development
- Extracting claims and expiration data
- Auditing JWT security headers
Verifies HS256 signatures using the browser's native SubtleCrypto API: no library, no server, cryptographic verification entirely in memory.
⚡ Off-thread · UI stays at 60fps
Encoded JWT
Signature Secret
Validation is performed locally using the browser's SubtleCrypto API. The secret is never transmitted.
Decoded Payload
Paste a JWT to inspect its contents.