Monitoring
SSL certificate monitoring
Days until the certificate expires, warned on the days you choose.
Free plan with 20 monitors. No card.
What it checks
SSL certificate monitoring
The default thresholds are 30, 14 and 7 days. Both ends of that range are wrong for somebody: 7 days is nothing for a certificate that needs a purchase order, and a monthly warning on a certificate that auto-renews at 30 days trains people to ignore the alert.
Renewals are noticed on the next check, so the warning clears itself.
- A TLS handshake against the host, reading the certificate the server actually presents.
- Days remaining until
notAfter, checked daily. - Warnings at the thresholds you set, not at ours.
It comes with the rest of the platform
Every monitor type shares the same alerting, the same status pages and the same map: escalation with on-call hours, a public status page, checks from independent networks, and agents for anything the internet cannot reach.
Questions
- Does it work with Let's Encrypt?
- Yes. It reads whatever certificate the server presents, from any issuer.
- Will it warn me about an expired certificate on a site that is otherwise up?
- Yes. Expiry is a separate monitor type precisely because the site keeps answering right up to the moment browsers stop trusting it.
- Does an invalid certificate break the check?
- No. A self-signed or expired certificate is a result, not an error: the check inspects rather than trusts.