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.

7 hosts · 270 ms

HostCertsFirst seenLast seenDNS
bigagency.com 4 2026-06-09 2026-08-18 ok
webdisk.bigagency.com 1 2026-08-18 2026-08-18 ok
cpanel.bigagency.com 1 2026-08-18 2026-08-18 ok
mail.bigagency.com 1 2026-08-18 2026-08-18 ok
app.bigagency.com 1 2026-04-11 2026-04-11 —
test.bigagency.com 1 2026-04-27 2026-04-27 nxdomain
www.bigagency.com 3 2026-07-10 2026-08-18 ok

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