Free · Check an RSA or EC signature

JWT Public Key Verifier

Verify an RS256 or ES256 token with a local public JWK or SPKI key.

  • Real jose checks
  • Private in your browser
  • Copy or download the result

Verify with key

A successful check proves this input matches this key. You must still trust the key source.

1Add the input
2Check the result
Your checked result will appear hereTry the safe sample if you do not have test data.
Private by design. Keys, secrets, claims, and messages never leave this tab. Do not paste a production private key on a shared device.

Three simple steps

How to use it

  1. Choose the token algorithm.
  2. Paste the matching public key.
  3. Verify before trusting the claims.

Your keys stay on this device

jose and Web Crypto do the work inside this browser tab. Bookify does not upload or save keys, secrets, tokens, or messages. A valid signature proves the input matches the key, but you must still trust where that key came from.