Free · Find a stable ID for a JSON Web Key

JWK Thumbprint Calculator

Calculate the RFC 7638 SHA-256 thumbprint and thumbprint URI for a JWK.

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

Calculate thumbprint

The input and result stay in this browser tab.

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. Paste one public or private JWK.
  2. Calculate its stable thumbprint.
  3. Copy the ID or URI.

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.