SSL Certificate Checker

Verify TLS certificate validity, expiry date, issuer chain, Subject Alternative Names, and cipher suite.

SSL/TLS certificate fields

Common Name (CN)Primary domain the certificate is issued for

SANSubject Alternative Names — all domains covered by the cert

IssuerCertificate Authority (CA) that signed the certificate

Valid From / ToCertificate validity window — expires at Valid To

Serial NumberUnique identifier assigned by the CA to this certificate

Cipher SuiteSymmetric encryption algorithm negotiated for this session

TLS ProtocolTLS version negotiated (TLSv1.2, TLSv1.3)

FingerprintSHA-1 hash of the certificate — used for pinning

Expiry monitoring best practices

Configure automated certificate renewal with Let's Encrypt Certbot or your cloud provider's managed TLS. Set monitoring alerts at 30 days and 7 days before expiry. Certificates from public CAs are now limited to 90-day validity, making automation essential.