Runs in your browser

Encoding & Security

JWT Signature Verifier

Verify supported HMAC, RSA, RSA-PSS, and ECDSA JWT signatures with a local key.

Runs locally in your browser
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About this tool

Verify a compact JWT signature locally using HS256/384/512, RS256/384/512, PS256/384/512, ES256, or ES384. The selected algorithm must match the token header and alg=none is rejected.

Common uses

  • Check an HMAC-signed development token
  • Verify RSA or EC tokens with an SPKI public key
  • Separate cryptographic signature status from authorization policy