Certificate Transparency Monitoring
Every SSL/TLS certificate issued by a public authority is recorded in Certificate Transparency (CT) logs — a public, append-only record. That means you can watch those logs for your own domains and find out, within minutes, when anyone obtains a certificate for them. If you didn't request it, that's an early warning: a phishing site impersonating you, a rogue or mis-issued certificate, or compromised DNS.
Uptime monitors tell you when your site goes down. CT monitoring tells you when someone else gets a certificate for your domain — a completely different, and often earlier, signal.
Check any domain's current SSL setup free — then set up CT monitoring below.
Why watch Certificate Transparency logs?
Spot phishing early
Attackers who clone your site need a certificate for a lookalike hostname. When it's issued, it shows up in CT logs — often before the phishing campaign even launches.
Catch rogue issuance
A certificate you didn't request can mean compromised DNS, a leaked registrar login, or a CA mistake. CT monitoring is how you find out it happened at all.
Discover forgotten hosts
CT logs are also an inventory of everything that exists. We use them to surface subdomains that hold certificates but aren't monitored — old staging boxes, a client's legacy host. See subdomain discovery.
How CT monitoring works here
- 1.Add a domain to monitoring in your dashboard. We take a silent baseline of the certificates that already exist, so you don't get alerted for your own current setup.
- 2.We poll Certificate Transparency logs on a schedule. When a new certificate appears for your domain or a subdomain, we email you the hostname, the issuer, and a link to the CT record.
- 3.Prefer Slack? Paid plans can send every alert to a webhook as well as email.
CT monitoring is part of the paid monitoring plans, alongside daily SSL-grade and security-header checks. The full-report checker above is free and needs no account.
Related: