PEM ↔ JWK Converter
Convert PEM-encoded keys to JSON Web Keys (JWK) and back using the Web Crypto API.
Supports RSA and EC (P-256 / P-384 / P-521). Everything runs in your browser — nothing is sent to a server.
PEM ↔ JWK controls
Frequently asked questions
What are PEM and JWK?
PEM is a Base64 text encoding of ASN.1 DER keys (BEGIN/END PUBLIC KEY or PRIVATE KEY blocks), widely used by OpenSSL and TLS. JWK (JSON Web Key) is a JSON representation of the same cryptographic key material, common in JOSE/JWT and Web Crypto APIs.
Which key types does this PEM ↔ JWK converter support?
RSA and elliptic-curve keys on P-256, P-384, and P-521. PEM input accepts SPKI (PUBLIC KEY), PKCS#8 (PRIVATE KEY), and common PKCS#1 wrappers (RSA PUBLIC/PRIVATE KEY; EC PRIVATE KEY when a named curve is present). Encrypted PEM is not supported.
Does my key leave my browser?
No. Conversion runs entirely in your browser with JavaScript and the Web Crypto API. Keys are not uploaded to a server. Prefer local tools for production secrets when possible.
Is this PEM ↔ JWK converter free?
Yes. The Formattly PEM ↔ JWK converter is free to use with no signup required.