← All Tools

JWK Inspector & Thumbprint

Paste a single JSON Web Key or a full JWKS document. The inspector validates the shape, classifies each key as public or private, surfaces kid, alg, use, and key_ops, and computes the canonical RFC 7638 SHA-256 thumbprint. Everything runs in your browser via the Web Crypto API — paste real keys safely.

About JWK & Thumbprints

A JSON Web Key (RFC 7517) represents a cryptographic key as JSON. The kty (key type) tells you the family: RSA, EC, OKP (Edwards / X-curve), or oct (symmetric). A JWKS is an object with a keys array — what an OIDC provider exposes at /.well-known/jwks.json.

The JWK Thumbprint (RFC 7638) is a stable, canonical hash of just the required public members for a given kty, sorted lexicographically and serialized without whitespace. It uniquely identifies the key material itself — two JWKs with the same thumbprint represent the same key even if kid, alg, or extra metadata differ. The default hash is SHA-256, base64url-encoded.

Required thumbprint members per spec: RSAe, kty, n · ECcrv, kty, x, y · OKPcrv, kty, x · octk, kty.