SSL monitoring

An SSL monitor checks the TLS certificate on a host and port, separately from any HTTP check you run against the same domain. This guide covers what it verifies and how expiry warnings work.

How it works

Stector connects to the hostname and port you configure, reads the certificate, and checks its expiry date. It does not validate the certificate chain or check that the hostname matches — only whether the certificate itself has expired.

Configuring the check

From /dashboard/monitors/new, choose SSL Certificate Check and set:

  • Hostname — the host to connect to.
  • Port — defaults to 443.
  • Warn before expiry (days) — how many days before the certificate expires Stector should send a warning. Leave it empty to disable warnings.

SSL monitors share the same Regions and Check interval options as HTTP monitors, but have no authentication fields — there's nothing to authenticate for a certificate check.

Warnings vs. incidents

An expiry warning is a notification, not an incident — it doesn't open an incident, and it doesn't affect your status page. It also bypasses maintenance-window suppression, so it still fires even if the monitor is covered by an active maintenance window (see Maintenance windows). Stector sends at most one warning per channel per calendar day while the certificate remains inside the warning window.

What happens when a certificate expires

Once the certificate's expiry date passes, the check fails like any other failing check, and the same down-incident flow applies — the monitor needs its usual region agreement (see Monitoring HTTP endpoints) before Stector opens an incident.

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