Find every subdomain
of a domain.

Every hostname under a domain that ever appeared in a public TLS certificate — with certificate counts and first/last seen dates.

20 hosts · 171 ms

HostCertsFirst seenLast seen
rule.se 51 2026-04-26 2026-09-23
*.rule.se 27 2026-05-11 2026-09-17
abc.rule.se 14 2026-05-31 2026-09-26
apidoc.rule.se 16 2026-05-30 2026-10-02
upfield.rule.se 16 2026-06-02 2026-09-28
staging.rule.se 7 2026-05-23 2026-09-21
track.rule.se 10 2026-05-05 2026-09-30
link.rule.se 18 2026-06-01 2026-09-28
gr.internal.rule.se 4 2026-06-08 2026-10-06
newgr.internal.rule.se 4 2026-06-11 2026-10-08
logs.internal.rule.se 3 2026-06-17 2026-08-16
cdn.rule.se 20 2026-05-31 2026-09-27
sitoo.rule.se 20 2026-05-31 2026-09-26
jetshop.rule.se 16 2026-05-31 2026-09-26
docs.rule.se 10 2026-05-31 2026-09-25
en.docs.rule.se 10 2026-05-31 2026-09-25
images.rule.se 20 2026-06-01 2026-09-28
files.rule.se 18 2026-06-01 2026-09-28
helpers.rule.se 25 2026-05-15 2026-09-27
www.rule.se 21 2026-04-26 2026-09-23

Programmatic access: API GET /v1/hosts/rule.se (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/rule.se.