Free · Sign with an RSA or EC private key

JWT Private Key Signer

Create an RS256 or ES256 token from claims and a local JWK or PKCS8 private key.

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

Sign with key

The input and result stay in this browser tab.

1Add the input

AlgorithmClaims JSONOne JSON object, up to 96 KB.Private JWK or PKCS8 keyUse the safe sample to generate a local test key.Key ID (kid)

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

Choose RS256 or ES256.
Paste a private JWK or PKCS8 key.
Sign and copy the token.

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.