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JWT (JSON Web Token) Decoder

Decode and inspect JWT tokens to see the header, payload, and signature. Perfect for debugging authentication.

What is JWT (JSON Web Token) Decoder?

A JSON Web Token (JWT) is a compact, URL-safe means of representing claims to be transferred between two parties. It is commonly used for authentication and authorization in web applications. A JWT consists of three parts separated by dots: the Header (containing the algorithm and token type), the Payload (containing the claims or statements about an entity), and the Signature (used to verify the token's integrity). Because the payload is only base64Url encoded—not encrypted—anyone can decode and read the contents, which is why sensitive data should never be placed in a standard JWT.

Common Use Cases

  • Debugging authentication flows in single-page applications (SPAs).
  • Verifying that OAuth2 or OpenID Connect tokens contain the correct user scopes and roles.
  • Checking the exact expiration time of a token to troubleshoot session timeouts.

Example: Input & Output

Sample Input

See the tool above for interactive examples.

Expected Output

The processed output will appear here instantly.

How to Use

  1. Step 1: Paste your encoded JWT into the input box.
  2. Step 2: The tool will automatically split the token into its Header and Payload parts.
  3. Step 3: Review the decoded JSON data to verify claims like expiration (exp), issuer (iss), or subject (sub).

Frequently Asked Questions

Does this tool verify the signature?

No, this tool only decodes the base64 URL-encoded header and payload. It does not cryptographically verify the signature.

Is it safe to paste my production JWT here?

Yes. This tool runs entirely client-side in your browser. Your token is never transmitted across the internet.

Is my data secure?

Yes. Everything is processed locally in your browser. No data is sent to our servers.

Privacy & Security

All data processing for the JWT (JSON Web Token) Decoder happens entirely on your local machine within your browser. No data is ever sent to our servers, ensuring your information remains private and secure. We believe in privacy by design, and our tools are built to be used without compromising your data.