SSL Certificate Decoder - Parse X.509 Certificates

Decode PEM-encoded X.509 certificates to view subject, issuer, validity, SANs, and more. All processing is local.

Frequently Asked Questions

What certificate formats are supported?

PEM-encoded X.509 certificates — the standard Base64 format enclosed in BEGIN/END CERTIFICATE markers.

What information can I extract?

Subject (CN, O, OU), issuer details, serial number, validity period, signature algorithm, public key info, and SANs.

Is my certificate data secure?

Completely. All decoding uses the forge.js library locally in your browser. No data is ever sent to a server.