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.

4 hosts · 311 ms

HostCertsFirst seenLast seenDNS
total.healthcare 18 2026-04-29 2026-09-20 ok
*.total.healthcare 16 2026-04-29 2026-09-20 —
mta-sts.total.healthcare 3 2026-04-20 2026-09-09 ok
www.total.healthcare 4 2026-05-08 2026-07-15 ok

Programmatic access, with DNS A records: API GET /v1/hosts/total.healthcare (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/total.healthcare.