Be explicit about uncertainty
Entry volumes are exact for these collectors; distinct certificate and domain totals are estimates. Start dates, expected error and known limitations are published alongside the figures.
Read the methodologyCT MONITORING
About
CT Monitoring provides an independent, readable view of the public Certificate Transparency ecosystem.
What we do
Our collectors follow public CT logs, verify their entries and produce aggregate measurements of the certificates and domain names observed. The public site receives summary snapshots every 15 minutes; it never receives the collectors' internal sketches or private monitoring watchlists.
Why it matters
TLS certificates are foundational to the web. Public logging makes issuance auditable, helps surface mistakes and supports monitoring for unauthorised certificates. Aggregate statistics also reveal the extraordinary scale and rate of change of the ecosystem.
Related monitoring
The collectors also support opt-in certificate monitoring for connected services such as DNSMON, with capacity for additional independent clients. Customer-specific results remain within the relevant service and are not exposed by this statistics site.
How we approach the data
Show collection health
Freshness and CT log coverage are visible so a number can be judged in context. Service interruptions and recoveries are recorded separately from the statistics.
Check live statusKeep public data aggregate
Only summary counts and coverage state reach this public site. Detailed collector records and private monitoring watchlists remain outside it.
Review privacy