ctlogs.dev
Search every public Certificate Transparency log for TLS certificates
About ctlogs.dev
ctlogs.dev is a search index for public Certificate Transparency logs, aimed at security teams, DevOps engineers and anyone who wants to audit which TLS certificates have been issued for a domain or organization. Users can search by hostname, wildcard domain, organization name, serial number or SHA-256 fingerprint and see the issuance record for each certificate.
The site continuously ingests the logs operated by major certificate authorities and log operators into one searchable index, and it lists dedicated tools for finding subdomains, checking CAA records, browsing BIMI brand logos and reviewing monitored log coverage. A free JSON API is available without a key for anonymous use with fair limits, and API keys raise the quota. Machine-readable docs are published for AI agents.
Its main difference from general certificate search is the stated depth of history: the site says it covers certificates back to 2013 and includes hostnames that no longer resolve in DNS.
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