X.509 Certificate & CSR Decoder
Inspect certificate metadata, chains, CSRs and public keys in PEM, DER or Base64 form without exposing the material to an online parser.
About X.509 & PEMFeatures & how to use
Inspect certificates and CSRs, convert JWK and PEM keys, inspect JWKS and calculate key thumbprints locally without uploading key material.
What it can do
- Inspect X.509 certificates, chains and certificate signing requests.
- Read subjects, issuers, SANs and fingerprints without network trust checks.
- Convert JWK to or from SPKI public and unencrypted PKCS#8 private PEM; inspect up to 100 JWKS keys.
- Calculate RFC 7638 SHA-256 key thumbprints. Public output strips secret parameters; private export requires explicit consent.
How to use it
- Paste certificate data or open a local file.
- Select Inspect.
- Review the parsed metadata and security boundaries.