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.

12 hosts · 373 ms

HostCertsFirst seenLast seenDNS
galco.com 33 2025-08-13 2026-09-18 ok
*.galco.com 35 2025-07-06 2026-09-18 —
staging.galco.com 16 2026-05-03 2026-08-29 ok
m.galco.com 8 2026-05-18 2026-09-13 ok
vpn.galco.com 6 2025-10-23 2026-08-27 ok
www.vpn.galco.com 6 2025-10-23 2026-08-27 nxdomain
docs.galco.com 1 2026-05-27 2026-05-27 ok
resources.galco.com 4 2026-05-14 2026-05-14 ok
mta-sts.galco.com 3 2026-06-20 2026-09-11 ok
content.galco.com 2 2026-08-12 2026-08-12 ok
portal-dev.galco.com 1 2026-07-28 2026-07-28 ok
email.www.galco.com 5 2026-05-03 2026-08-31 ok

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