DOCUMENTATION

certs.

One-off check, no account

POST /certs/v1/certs/check-now with a JSON body {"domain": "example.com"} returns the active TLS certificate (protocol and cipher suite), six kinds of DNS records (A, AAAA, MX, NS, TXT, CNAME), the domain expiry date at the registry, and a web-security section (HSTS, security headers, mixed content). The A–F grade is computed in your browser from those results. Limited to 20 requests per minute per IP address.

What the free tier covers

Unlimited one-off checks: paste any domain and get its TLS certificate, DNS records and expiry date instantly -- graded A–F, with a shareable link and a calendar reminder. History kept.