Find every subdomain
of a domain.

Every hostname under a domain that ever appeared in a public TLS certificate — with certificate counts, first/last seen and live DNS status.

6 hosts · 259 ms

HostCertsFirst seenLast seenDNS
falltech.com 17 2025-07-24 2026-09-20 ok
*.falltech.com 8 2026-05-13 2026-09-20 —
blog.falltech.com 12 2026-05-01 2026-08-27 ok
portal.falltech.com 5 2026-05-03 2026-09-01 ok
idp.falltech.com 5 2026-04-22 2026-08-20 ok
www.falltech.com 7 2025-07-24 2026-09-19 ok

Programmatic access, with DNS A records: API GET /v1/hosts/falltech.com (API key for paging).

Shown here: hostnames with a certificate that is valid now or expired within the last 90 days. The full history since 2013 — hostnames whose last certificate expired earlier — is a Pro plan method: GET /v1/hosts-history/falltech.com.