Skip to content
dnsdon

SSL Certificate Checker

Check whether a site serves HTTPS, when its certificate expires, whether browsers will trust it, and how HTTP traffic is redirected.

Enter a domain or hostname. Pasted URLs and internationalized names work too.

For TLS services on other ports, such as 8443, 465 (SMTP), 993 (IMAP) or 853 (DNS over TLS). Redirect and HSTS checks run on port 443 only.

Checking github.com

Resolving the hostname…