Cryonel

JWKS to PEM Converter

Paste a JWKS (JSON Web Key Set) or a single JWK — RSA or EC — and convert it to PEM format, the format most TLS libraries, OpenSSL, and Cryonel's own JWT Decoder expect.

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How to use it

Paste a full JWKS ({"keys":[...]}) or a single JWK object. If the set has more than one key, pick one from the dropdown by its kid. Both RSA and EC (P-256/P-384/P-521) keys are supported. The output is always a public key in SPKI PEM format.

Frequently Asked Questions

Where do I get a JWKS?

Most OAuth/OIDC identity providers publish one at a /.well-known/jwks.json endpoint. Fetch it yourself and paste the contents here — this tool doesn't fetch URLs for you, to keep every Cryonel tool free of outbound network calls.

Can I convert a private key?

No — JWKS entries published by identity providers are public keys only (that's the point: they're safe to publish). This tool only produces public-key PEM output.

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