CT Log Search

Searches Certificate Transparency logs for certificates issued to a domain, surfacing subdomains that have had a TLS certificate issued for them — including ones that were never publicly linked from anywhere. Since 2018, virtually all publicly trusted certificate authorities are required to log every certificate they issue to public CT logs, which means any subdomain that's ever gotten a valid cert leaves a permanent, searchable record. Queries certspotter.com as the primary source with a crt.sh fallback for reliability.

A hit in this search only proves a certificate was issued at some point — the subdomain, and even the certificate itself, may no longer be active or valid by the time you see the result.

📖 Read more in our Knowledge Base →