ctlogs.dev - Certificate Transparency Search

ctlogs.dev searches the public Certificate Transparency logs, where every publicly trusted TLS certificate is recorded. Connected to it, Claude can answer questions such as "which subdomains does example.com have", "who issued the certificates for this name" or "which domains does this company hold certificates for".

Tools (all read-only):

• find_subdomains: the hostnames found under a domain in TLS certificates, with the number of certificates and first/last seen dates.
• search_certificates: the certificates issued for a domain name, with issuer, serial number and validity dates.
• search_organization: the certificates whose subject organization matches a name.
• get_certificate: the full record of one certificate, including its DNS names and the CT log entries that recorded it.
• get_ca: one issuing CA certificate and the certificates it issued.

Results cover certificates that are valid now or expired within the last 90 days.

The server works at once, without an account, up to the anonymous limits. Past them Claude asks you to sign in with GitHub, Google or an e-mail link; a new account gets a free API key with 10,000 credits a month for testing and non-commercial use.