ChistStudioHow this check works
Two independent signals are combined: a live HTTPS connection attempt, which tells you right now whether the certificate is valid and trusted, and a lookup against public Certificate Transparency logs, which surfaces the issuer and validity window of the most recently issued certificate for the domain — useful for catching an upcoming expiry before it causes an outage.
Frequently asked questions
What happens when an SSL certificate expires?
Browsers show a prominent warning and block the connection by default, since identity can no longer be verified — an immediate, full trust outage even if the site itself works fine.
What is Certificate Transparency?
A public, append-only log of every publicly trusted TLS certificate issued, created to detect fraudulent or mistaken issuance, and useful as a public audit source.
Why might the live check and the Certificate Transparency data show different dates?
The live check confirms current trust status; the CT log shows the most recently logged certificate, usually the same one but occasionally lagging during a renewal window.