Free tool
SSL checker
Enter a hostname. We connect from Frankfurt, read the certificate the server presents, and tell you when it expires and who issued it.
Why does the expiry date matter if renewal is automatic?
Because it is automatic until the day it is not: a changed DNS record, a revoked API key or a full disk stops the renewal, and nothing tells you until the browser does.
What does "served over HTTPS" check?
That the site answers on port 443 with a certificate that matches the hostname and chains to a trusted root, and that plain HTTP sends visitors there.