SSL Monitoring
Automatic certificate tracking and expiry alerts for every HTTPS monitor.
Overview
SSL certificate monitoring is automatic for all HTTPS monitors. There is nothing to configure. When you add a monitor with an https:// URL, Notifier checks your certificate once every 24 hours and sends you alerts as the expiration date approaches.
What Gets Checked
Every 24 hours, Notifier opens a direct TLS connection to your server (with a 10 second timeout) and inspects the following:
- Expiration date — when the certificate will expire
- Certificate issuer — the authority that issued the certificate (e.g. Let's Encrypt, DigiCert, Sectigo)
- Certificate validity — whether the certificate chain is valid and trusted
Expiry Alerts
Notifier sends warning emails at four thresholds before your certificate expires:
| Days Before Expiry | Alert |
|---|---|
| 30 days | First warning email |
| 14 days | Second warning email |
| 7 days | Third warning email |
| 1 day | Final warning email |
Each threshold fires once per certificate. When you renew your certificate, the tracking resets and all four thresholds will fire again for the new certificate.
Expired Certificates
If your certificate has already expired, Notifier marks the monitor status as DOWN. Modern browsers block connections to sites with expired certificates entirely, so an expired certificate means your site is effectively unreachable for visitors.
SSL Errors
If the certificate is invalid, self-signed, or the TLS connection cannot be established, Notifier displays the error on the monitor card as a warning. This does not mark the monitor as DOWN.
The ssl_error field on the monitor shows what went wrong. Common SSL errors include:
- Self-signed certificate
- Certificate hostname mismatch
- Incomplete certificate chain
- Connection timed out during TLS handshake
Viewing SSL Details
You can view the certificate expiration date and issuer on the monitor detail page. Open any HTTPS monitor and look for the SSL section below the uptime chart.
Plan Availability
SSL monitoring is available on all plans, including Free. It activates automatically for every HTTPS monitor. There is no configuration needed and no extra cost.