Certificate Decoder
Decode an SSL/TLS certificate into readable details — subject, issuer, validity, SANs and fingerprints.
Frequently Asked Questions
What does the certificate decoder show?
It shows the subject, issuer, validity dates, covered domains (SANs) and key details of a PEM certificate without installing anything.
What is a SAN in a certificate?
SAN ("Subject Alternative Names") is the list of all domains a certificate covers; modern certificates use SAN even for a single domain.