JWK (JSON Web Key)

A JSON data structure defined in RFC 7517 for representing a cryptographic key — RSA, EC, or symmetric — including its key type, algorithm, and public key parameters. A JWK Set (JWKS) is a JSON array of JWKs served from a well-known endpoint (typically /.well-known/jwks.json) that allows resource servers and relying parties to fetch the current public keys for verifying JWTs without out-of-band key distribution.