SSL/TLS Certificate Checker
Inspect a server's TLS certificate — expiry, issuer, SANs, chain, protocol.
About this tool
Connects to the host on the given port (default 443) and parses the served certificate. Flags expiry, self-signed certs, untrusted chains, and outdated TLS versions.
FAQ
- Why does the SAN list include extra hosts?
- Modern certificates often cover many hostnames (e.g. wildcard CDN certs cover thousands). The SAN extension lists every name the certificate is valid for.