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.

15 hosts · 314 ms

HostCertsFirst seenLast seenDNS
thecooldown.com 6 2026-05-31 2026-10-02 ok
pea.thecooldown.com 9 2026-04-14 2026-08-14 ok
c9b4dc.thecooldown.com 3 2026-04-14 2026-05-17 ok
subscribe.thecooldown.com 8 2026-05-06 2026-08-28 ok
guide.thecooldown.com 5 2026-05-14 2026-09-15 ok
rs-stripe.thecooldown.com 5 2026-05-22 2026-09-20 ok
trk.thecooldown.com 10 2026-04-25 2026-08-22 ok
platform.thecooldown.com 5 2026-05-21 2026-09-21 ok
greenscreen.thecooldown.com 5 2026-04-25 2026-08-27 ok
join.thecooldown.com 5 2026-06-05 2026-09-26 ok
learn.thecooldown.com 1 2026-08-17 2026-08-17 ok
links.thecooldown.com 3 2026-06-06 2026-08-14 ok
rcms.thecooldown.com 1 2025-12-12 2025-12-12 ok
widgets.thecooldown.com 4 2026-04-10 2026-08-08 ok
www.thecooldown.com 6 2026-05-31 2026-10-02 ok

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