SSL certificate monitors

Markdown

Get warned before an SSL/TLS certificate expires.

An SSL monitor connects to your service, inspects its certificate, and warns you well before it expires. An expired certificate makes browsers show a scary warning and can take a site down instantly — this monitor makes sure that never surprises you.

An SSL monitor's detail panel, showing the certificate is valid with 22 days remaining before expiry, alongside its check interval and alert thresholds The countdown to expiry is shown on the monitor itself, so you see it without opening anything.

Setting it up

  • Target — the domain to check, e.g. example.com. It checks port 443 by default; add :port if your TLS service runs elsewhere.

What it tracks

  • Days until expiry, shown right on the monitor.
  • Issuer and validity dates.
  • Whether the certificate is already expired (which reads as down).

Expiry alerts

You choose two thresholds per monitor:

  • Warning — how many days before expiry to send a first heads-up (default: 14 days).
  • Critical — a more urgent reminder as the deadline approaches (default: 7 days).

Both are adjustable from 1 to 365 days, and the critical threshold must be sooner than the warning one.

Good to know

  • An SSL monitor reports on the certificate even if the chain is self-signed or expired — its job is to tell you the state of the cert, not to block on it.
  • It's independent of your HTTP monitor: run both so you're covered for "site is down" and "cert is about to lapse".

Get started

Last updated 2026-07-15