Online JWT Decoder & Debugger

100% In-Browser & Private

Decode JSON Web Tokens (JWT) in real-time to inspect token headers, user claims, expiration timestamps, and algorithms in complete privacy.

About JWT Debugger & Decoder

JSON Web Tokens (RFC 7519) are an open standard for securely representing claims between parties in modern authentication (OAuth 2.0, OpenID Connect). A JWT is divided into three parts separated by dots: Header, Payload, and Signature. DeveloperToolz decodes the base64url-encoded parts into formatted JSON so you can inspect claims like exp, iat, and roles safely.

Key Features & Capabilities

Decodes JWT Header and Payload sections into formatted JSON
Human-readable expiration timestamp inspection
Zero security risk: your authentication tokens are NEVER transmitted across the internet
Visual validation for invalid or malformed tokens

How to Use This Tool

  1. 1

    Paste token

    Paste your encoded JWT into the token input field.

  2. 2

    Inspect decoded claims

    Review the formatted JSON output showing the Header algorithm and Payload claims.

  3. 3

    Copy claims

    Easily copy individual sections or claim payloads.

Frequently Asked Questions

Is it safe to paste private JWT tokens here?

Yes! Unlike other online JWT debuggers that send tokens to backend servers, DeveloperToolz performs 100% of the decoding in your client browser. No tokens are ever logged or uploaded.

What do the three parts of a JWT represent?

The Header defines the token type and signing algorithm (e.g. HS256, RS256); the Payload contains the claims/user data; and the Signature verifies that the sender is who it says it is and that the message wasn't changed along the way.

Client-Side Security Guarantee: All operations are processed locally in your browser sandbox using web standards. We never record, send, or store your code, data payloads, or tokens on any server.