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.

9 hosts · 284 ms

HostCertsFirst seenLast seenDNS
michealthcare.com 17 2025-07-28 2026-10-04 ok
*.michealthcare.com 12 2025-07-28 2026-10-04 —
track.michealthcare.com 1 2025-12-11 2025-12-11 ok
www.track.michealthcare.com 1 2025-12-11 2025-12-11 nxdomain
ascension.michealthcare.com 3 2026-05-19 2026-09-03 ok
q.michealthcare.com 1 2026-01-01 2026-01-01 ok
www.q.michealthcare.com 1 2026-01-01 2026-01-01 nxdomain
demo-test.michealthcare.com 2 2026-07-22 2026-07-22 ok
www.michealthcare.com 5 2026-05-16 2026-09-13 ok

Programmatic access, with DNS A records: API GET /v1/hosts/michealthcare.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/michealthcare.com.