Decode an X.509 Certificate
Paste a PEM-encoded certificate below. Everything is parsed in your browser — nothing is sent to our server.
About This Tool
This PEM decoder parses X.509 certificates entirely in your browser. The certificate never leaves your machine — there's no network request when you click Decode.
It extracts the subject, issuer, validity period, serial number, signature algorithm, public key information, Subject Alternative Names (SANs), and computes SHA-1 and SHA-256 fingerprints.
Need to generate a self-signed certificate? Use our free generator — same privacy guarantees.