SSL certificate checker

QUESTIONS ABOUT THIS TOOL

What happens to my SEO if the certificate expires?

Browsers show a full page interstitial, so real visitors bounce before they see the page. Googlebot cannot complete the handshake either, so pages stop being recrawled and eventually drop out of the index. An expired certificate is a total outage, not a warning.

My certificate is valid but the browser still complains. Why?

Almost always a missing intermediate. Your server has to send its own certificate and the intermediate that signed it. Browsers on desktop often paper over the gap from cache, which is why the problem shows up on a colleague's phone and not on yours. This tool walks the chain the server actually sent.

What counts as too close to expiry?

Under 30 days is worth acting on, under 14 is a real risk, because a certificate that expires on a Saturday takes the site down until someone notices. If your certificate is issued for 90 days or fewer, renewal is almost certainly automated and the number to watch is whether the automation last ran.

Does a more expensive certificate rank better?

No. Google's signal is HTTPS or not HTTPS. A free certificate from a public authority and a paid extended validation certificate are worth exactly the same for ranking. Pay for one only if you want the warranty or the organisation vetting.

What does 'does not cover this hostname' mean?

The certificate is real, but the name you asked for is not in its list of subject alternative names. This is the classic www problem: a certificate for example.com that does not list www.example.com, so half your visitors get a warning. Both names have to be on it.

Do you connect to my server?

Once, to port 443, to complete a TLS handshake and read the certificate the server presents. We send no request, no data, and no credentials, and we close the socket immediately. The port is fixed and cannot be changed.