About this tool

CTlogs.io indexes the public Certificate Transparency logs into a searchable index of 45B+ certificate records covering 638M domains. Four queries: the subdomains of a registered domain, the certificates issued for a hostname, a certificate by SHA-256 fingerprint, and a keyword search over the last few weeks of issuance, which is where new phishing and look-alike hostnames first appear. Results show issuer, SANs, validity window and when the certificate was first logged.

Guests get 3 searches a day and a free account 5 a day per query type, no card. Paid plans ($29.99, $69.99 and $149.99 a month) add CSV export, a REST API with hourly quotas and an MCP connector so AI assistants can query the index. Six free tools need no account: subdomain finder, SSL certificate history, certificate expiry checker, certificate authority lookup, fingerprint lookup and a brand impersonation scanner. Built by the team behind abtdomain.com.