How to use JWT Signature Verifier

  1. Paste your shared secret key on the first line.
  2. On the following line, paste the full JWT (header.payload.signature).
  3. Click Validate to check whether the signature matches for HS256, HS384, or HS512.

Example

Input

my-secret-key
eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VySWQiOjF9.DUMMY_SIGNATURE

Output

{
  "valid": false,
  "algorithm": "HS256",
  "reason": "Signature does not match for the provided secret."
}

Frequently asked questions

Which JWT algorithms are supported?
This verifier supports HS256, HS384, and HS512 using a shared secret. It does not verify RS256 or other asymmetric algorithms.
Does this tool store my JWT or secret?
Verification is performed in your browser using the Web Crypto API. Secrets and tokens are not stored on the server.

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