That said, crt.sh can be woefully unreliable. It often returns errors during a query or is just hard down. Large result sets may never return. Queries often take a very long time.
I wanted a more reliable CT log search tool for something I'm working on, so I built a purpose built CT log search tool. I ingest all the data from the logs directly and store in Clickhouse.
CertRadar has four free tools (no signup, no premium tier):
- CT Log Search – find every certificate ever issued for a domain via Certificate Transparency logs. Great for discovering forgotten subdomains.
- SSL Analyzer – cert chain, TLS versions, HSTS, expiration. Faster than SSL Labs.
- DNS + SSL Check – DNS records and SSL health in one view.
- Security Headers – HSTS, CSP, X-Frame-Options analysis with recommendations.
Built with Rust on GCP Cloud Run. Happy to talk about the architecture or any feedback on what would make these more useful.
Log Whois and now RDAP JSON
Log DNS zones
Find typo squatting