SSL Certificate Checker
Verify that a website's certificate is trusted, see exactly when it expires and which domain names it covers.
What this SSL checker verifies
We open a TLS connection to the domain on port 443 and validate the certificate the server presents, exactly as a browser would: is it issued by a trusted certificate authority, does it cover the domain name, and is it within its validity period?
We then show the certificate details, including the issuer, the exact expiry date and all domain names it covers, together with the negotiated TLS version.
Why certificate expiry causes outages
When a certificate expires, browsers show a full-page security warning and most visitors leave. Automated renewal (for example with Let's Encrypt and the ACME protocol) prevents most of these incidents, but renewals can fail silently. Checking the expiry date regularly is a simple safeguard. UptimeStats records the expiry date on every HTTPS check of the websites you monitor.
Read more in What Is an SSL Certificate and Why Is It Important?
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