What does PEM / X.509 Certificate Decoder actually do?

The certificate decoder parses a PEM or DER-as-text X.509 certificate and shows subject, issuer, validity, and related fields. It does not check revocation, does not build a chain to a trusted root, and does not prove the server you connect to presented this certificate.

When should I use PEM / X.509 Certificate Decoder?

Use it to read dates and names from a PEM you were sent.

When should I not use PEM / X.509 Certificate Decoder?

Do not treat a successful parse as trust.

What does PEM / X.509 Certificate Decoder not do?

No OCSP or CRL check. A decoded cert can still be expired, self-signed, or for a different hostname.

PEM / X.509 Certificate Decoder

Decode PEM or base64 X.509 certificates — subject, issuer, SANs, dates, fingerprints. Free online — runs locally, no upload.

PEM / Base64 certificate

Search tools

PEM / X.509 Certificate Decoder