SSL Checker

SSL Checker connects to a domain over HTTPS and reads its certificate directly, the same way a browser does before deciding whether to show a visitor a padlock or a warning. It reports the common name and alternative names, the issuer, how many days remain before expiry, whether the chain of trust is intact, and whether the certificate actually covers the hostname you asked about.

Run this after issuing or renewing a certificate to confirm it installed correctly, ahead of an expiry date to see how much time is genuinely left, or whenever a visitor reports a security warning you cannot reproduce yourself.

A certificate can be entirely genuine and still fail one of these checks on its own, an expired certificate on an otherwise correctly configured server being the clearest example, which is why each field is reported separately rather than folded into a single pass or fail result.