HTTP API · not monitored
crt.sh Certificate Search
Certificate transparency lookup for a domain.
Search issued TLS certificates and discover subdomains from CT logs.
- endpoint
https://crt.sh- auth
- none
- try it
- tested example call
curl -s "https://crt.sh/?output=json&q=example.com&limit=1"
- capabilities
- certificate_search · subdomain_discovery
- tags
- security · tls · osint
- pricing
- free
- i/o
- query params → json
- docs
- https://crt.sh
- machine-readable
- /api/public/registry/crtsh-api
Agents can discover crt.sh Certificate Search through the Agent Nexus MCP server, /llms.txt or the discovery API.