JWT Decoder & Debugger - No Key Upload, Private Local Tool

Decode and debug JWTs in your browserโ€”no secret key, no uploads. Inspect header/payload, pretty-print JSON, and see a live exp countdown. Paste offline now.

Header
{}
Payload
{}

How to Use

  1. Paste your JWT (often starts with ey...) into the input.
  2. The tool decodes header and payload and formats them as JSON.
  3. Review status: active / expired / not-yet-valid.
  4. Copy the decoded JSON to share internally or debug safely.

Core Features

  • Client-side Decoding: Decode JWTs locally with zero key upload and zero server calls.
  • Expiration Countdown: Calculate remaining time from the exp claim with a live countdown.
  • Visual Payload Inspector: Inspect claims clearly to debug roles, audience, issuer, and scopes.
  • JSON Pretty Print: Beautify header and payload automatically for fast troubleshooting.
  • Keep data private: Tokens stay in memory on your device.

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Calculation Logic

  • A JWT is header.payload.signature.
  • We Base64Url-decode the first two parts and JSON.parse them for inspection.
  • We do not verify the signature (verification requires a secret/public key), so readable does not mean trusted.

FAQ

Is it safe to paste my JWT here?

Yes. We never ask for your secret key, and decoding runs 100% in your browser with no uploads.

How to check when a JWT expires?

We read the exp claim and compute the remaining time from now, showing a live countdown.

Is my data safe (local/privacy)?

Yes. Tokens are processed locally and are not sent, stored, or logged by a server.

Is it free? Any limits?

Itโ€™s free. For security, avoid pasting production tokens on shared/public devices.

Can I verify a JWT without a key?

No. Signature verification requires the correct secret/public key. This tool is for decoding and debugging claims only.