SSL Certificate Checker
Check any site's HTTPS certificate - expiry countdown, issuer, protocol and covered domains.
This tool inspects a website's TLS/SSL certificate - checking its expiry date, issuer, Subject Alternative Names (SANs), and the full certificate chain. Useful for verifying a certificate is valid and won't expire soon, or diagnosing HTTPS trust issues on your own or another site.
Frequently asked questions
Browsers will show visitors a security warning and typically block easy access to the site, since an expired certificate can no longer be trusted to verify the site's identity - this is why monitoring expiry dates matters, especially for production sites.
Additional domain names covered by the same certificate - for example, a certificate might cover both "example.com" and "www.example.com" as SANs, so both work correctly under HTTPS with one certificate.
It shows whether the certificate is properly linked back to a trusted root certificate authority through any intermediate certificates - a broken or incomplete chain can cause trust errors in some browsers/devices even if the certificate itself is technically valid.