What is a SSL certificate?

The file that gives your website the padlock and keeps what visitors type private.

An SSL certificate (today it is technically called TLS, but everyone still says SSL) is what makes a website address start with https and show a padlock in the browser. It proves the site is really yours and scrambles the information that travels between the visitor and your site.

Certificates expire, usually every 90 days or once a year. When one expires, browsers show a full-page warning and most people leave. Payment pages, booking forms and logins all stop being trusted.

Most hosts renew certificates automatically. When that automation breaks, nobody notices until the warning appears. That is the gap this service watches.

What to do

Know who issues your certificate: your host, Cloudflare or a provider like Let's Encrypt.
Set a reminder 14 days before expiry even if renewal is automatic.
If you see a browser warning on your own site, do not type passwords into it. Call your host.