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Free Online JWT Security Inspector

Inspect JWT claims, check token expiration, algorithms, and decode claims client-side.

Security Notice: This tool decodes JWT data but does not verify the token signature. All decoding is processed locally in your browser and is never sent to a server.
Header: Algorithm & Token Type
Header JSON will appear here...
Payload: Data Claims
Payload JSON will appear here...
Client-Side Guarantee: Processed 100% locally in your browser. No files or data are uploaded.

How to Use the JWT Security Inspector

  1. Paste a JWT into the inspector.
  2. Review algorithm security warning and claims breakdown.
  3. Check expiration status.

Key Features

Flags dangerous 'none' algorithm
Calculates remaining token validity
Decodes all standard claims (exp, nbf, iat, aud)
Client-side private inspection

About JWT Security Inspector

Analyze JSON Web Tokens for security vulnerabilities: flags 'alg: none', checks expiration timestamps against current time, and decodes claim payloads.

Frequently Asked Questions

Does this tool transmit my token over the internet?

No. Decoding is performed purely client-side; tokens are never sent across the network.

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