Enter a domain to inspect its SSL/TLS certificate the same way a browser does. An expired certificate, a missing domain or an incomplete chain shows visitors a security warning and blocks the website.
Free and without registration. The check is made from our server, so the timings include the network distance to it.
Browsers show a full-page security warning and most visitors leave. Search engines may also stop showing the page. Free Let's Encrypt certificates are valid for 90 days, so renewal must be automated.
A certificate covers only the domains listed in it. If www.example.com is not in the list, browsers reject the connection before any redirect happens. Add both names when issuing the certificate.
The server must send its certificate together with the intermediate certificates of the issuer. Some browsers can fill the gap themselves, others (and many API clients) cannot and show an error. Use the full chain file (fullchain.pem) in the server configuration.
One request shows the best case. Run a free load test with up to 1,000 concurrent connections, compare the results after every change and get an email when your site goes down.
Run a free load test