JWT Debugger: Decode & Verify JSON Web Tokens in Your Browser

JWT Debugger — Free Online Tool

Need to quickly inspect a JWT token? JWT Debugger lets you decode and verify JSON Web Tokens entirely in your browser — no data leaves your machine.

Features

• Color-coded visualization — header (pink), payload (purple), signature (teal) at a glance
• HMAC signature verification — HS256/HS384/HS512 via Web Crypto API
• Claim inspector — registered claims (iss, sub, aud, exp, nbf, iat, jti) with human-readable timestamps
• Expiry status — shows remaining time or expired badge
• Algorithm detection — auto-detects alg from header
• Three views — Visual, Raw JSON, Claims grid
• Base64-encoded secret support

How to Use

1. Paste your JWT token in the input box
2. The token is instantly decoded into header and payload
3. Enter your HMAC secret to verify the signature
4. Switch tabs to inspect individual claims

Why Client-Side?

JWT tokens often contain sensitive information (user IDs, roles, permissions). A client-side tool means your tokens never touch a server.

Try It

https://jwt-debugger-abe.pages.dev

Part of the DevNest.io collection of free developer tools.