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.

3 hosts · 363 ms

HostCertsFirst seenLast seenDNS
getsquareone.app 10 2026-04-15 2026-08-12 ok
sendit.getsquareone.app 4 2026-05-18 2026-09-10 ok
www.getsquareone.app 9 2026-04-16 2026-08-12 ok

Programmatic access, with DNS A records: API GET /v1/hosts/getsquareone.app (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/getsquareone.app.