SSL Checker

Check an SSL certificate in seconds

An SSL (TLS) certificate lets browsers open your site over HTTPS, shows the padlock and protects logins, forms and payments from being read or changed on the way. When a certificate expires or does not cover the name a visitor typed, browsers show a full-page warning and most people leave. This checker shows which certificate covers your domain, who issued it, when it expires and whether your server answers over HTTPS right now.

What the checker reports

• Verdict: whether HTTPS works and how many days the newest certificate has left, with a green, amber or red badge.
• Issuer: the certificate authority, such as Let's Encrypt, Google Trust Services, Sectigo or DigiCert.
• Validity: the valid-from and valid-to dates in UTC.
• Covered names: every host name (Subject Alternative Name) the certificate is valid for, including wildcards.
• HTTP to HTTPS: whether plain HTTP visitors are redirected to the secure version.
• Recent certificates: other unexpired certificates for the name, so you can spot a renewal or a forgotten server.

How Certificate Transparency helps

Since 2018 browsers only trust certificates that have been written to public Certificate Transparency logs. That makes the logs a reliable record of every certificate for your domain. Site owners also use them to catch certificates they did not request, which can be an early sign of a hijacked DNS account or a misused hosting panel.

Fixing common problems

If the days left are low, check that your hosting panel or certbot timer is still renewing. If HTTPS fails while a valid certificate exists, the server may not have the new certificate installed or port 443 may be closed. If HTTP does not redirect, add a permanent 301 redirect to HTTPS and consider HSTS once everything works.