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.

22 hosts · 265 ms

HostCertsFirst seenLast seen
masterplan.com 63 2026-03-31 2026-09-22
*.masterplan.com 36 2026-04-22 2026-09-22
media.masterplan.com 6 2025-07-08 2026-08-25
image.smc.masterplan.com 2 2026-01-21 2026-01-21
img.masterplan.com 10 2026-05-07 2026-09-02
blog.masterplan.com 10 2026-04-24 2026-08-20
*.mail.masterplan.com 20 2026-05-10 2026-09-15
link.mail.masterplan.com 5 2026-06-05 2026-10-03
vlearn.masterplan.com 2 2025-07-14 2026-06-14
*.vlearn.masterplan.com 12 2025-07-14 2026-09-15
lp.masterplan.com 10 2026-04-23 2026-08-19
up.masterplan.com 1 2026-01-29 2026-01-29
jobs.masterplan.com 4 2026-04-16 2026-08-14
hs.masterplan.com 10 2026-04-23 2026-08-19
plans.masterplan.com 12 2026-05-22 2026-09-17
developers.masterplan.com 5 2026-04-30 2026-08-29
mta-sts.masterplan.com 4 2026-04-21 2026-08-19
status.masterplan.com 7 2026-06-01 2026-10-06
support.masterplan.com 4 2026-06-10 2026-10-08
www.masterplan.com 1 2026-03-31 2026-03-31
pay.masterplan.com 10 2026-05-21 2026-09-16
buy.masterplan.com 12 2026-05-23 2026-09-21

Programmatic access: API GET /v1/hosts/masterplan.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/masterplan.com.