JWT Debugger | Decode, Edit, and Verify JWTs Locally

Secure, client-side JWT debugger. Decode JSON Web Tokens, edit the payload, and verify signatures locally without your secret keys ever leaving your browser.

JWT Debugger

Signatures are generated entirely locally using Web Crypto API. Tokens never leave browser.

Encoded Token

Header: Algorithm & Token Type

{
  "alg": "HS256",
  "typ": "JWT"
}

Payload: Data

{
  "sub": "1234567890",
  "name": "John Doe",
  "iat": 1516239022
}

Verify Signature

Secret Key

Signature status unknown (Enter secret)

Advanced JWT Manipulation
& Testing Suite

Essential for bug bounty hunters and penetration testers. Modify JWT payloads and test for signature vulnerabilities directly in your browser. Supports "none" algorithm testing and secure signature verification locally.

100% Local•Zero Latency•Open Logic

JWT Debugger | Decode, Edit, and Verify JWTs Locally

Advanced JWT Manipulation & Testing Suite

Advanced JWT Manipulation
& Testing Suite