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.

12 hosts · 277 ms

HostCertsFirst seenLast seen
postr.com 15 2026-05-24 2026-09-21
link.postr.com 1 2025-10-13 2025-10-13
portal.postr.com 3 2026-04-20 2026-09-20
gtm.postr.com 3 2026-05-04 2026-08-21
admin.postr.com 3 2026-04-24 2026-09-24
images.postr.com 2 2025-10-08 2026-09-08
videos.postr.com 3 2026-05-06 2026-10-06
u.postr.com 2 2026-04-02 2026-09-02
*.u.postr.com 2 2026-04-02 2026-09-02
www.postr.com 27 2026-05-23 2026-09-19
index.postr.com 2 2026-05-08 2026-10-08
*.index.postr.com 2 2026-05-08 2026-10-08

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