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.

23 hosts · 255 ms

HostCertsFirst seenLast seenDNS
serko.com 14 2026-05-19 2026-09-14 ok
*.serko.com 1 2026-08-14 2026-08-14 —
brand.serko.com 10 2026-05-23 2026-09-19 ok
fileshare.serko.com 11 2026-05-01 2026-10-01 ok
architecture.serko.com 2 2026-02-12 2026-07-06 ok
expense.serko.com 2 2026-06-02 2026-06-03 ok
training.serko.com 4 2026-04-15 2026-08-18 ok
portal.serko.com 2 2026-01-18 2026-06-12 ok
help-platform.serko.com 9 2026-05-24 2026-09-19 ok
jn1a-vvpn.serko.com 1 2026-02-04 2026-02-04 ok
l78a-vvpn.serko.com 3 2026-02-04 2026-03-10 ok
1mhb-vvpn.serko.com 1 2026-02-04 2026-02-04 ok
nw8c-vvpn.serko.com 1 2026-02-04 2026-02-04 ok
fnmg-vvpn.serko.com 1 2026-02-04 2026-02-04 ok
laah-vvpn.serko.com 1 2026-02-04 2026-02-04 ok
analytics.serko.com 1 2026-02-09 2026-02-09 nxdomain
nps.serko.com 1 2025-07-15 2025-07-15 nxdomain
partners.serko.com 1 2025-12-29 2025-12-29 ok
bookingforbusiness.serko.com 1 2026-08-18 2026-08-18 ok
mta-sts.serko.com 3 2026-04-24 2026-09-14 ok
help-ict.serko.com 12 2026-05-24 2026-09-19 ok
intranet.serko.com 5 2026-04-15 2026-09-24 ok
www.serko.com 10 2026-05-07 2026-09-03 ok

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