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.

21 hosts · 271 ms

HostCertsFirst seenLast seen
popsa.com 7 2025-08-11 2026-08-31
*.popsa.com 2 2025-08-11 2026-07-10
share.popsa.com 16 2026-04-18 2026-08-15
test-share.popsa.com 13 2026-05-04 2026-08-30
staging.popsa.com 2 2025-07-02 2026-06-02
blog.popsa.com 2 2025-07-05 2026-06-03
link.popsa.com 3 2026-05-27 2026-09-11
link.mail.popsa.com 5 2026-05-06 2026-10-06
web.design-system.popsa.com 4 2026-04-19 2026-08-17
open.popsa.com 8 2026-04-19 2026-08-15
test-open.popsa.com 12 2026-05-05 2026-09-01
app.popsa.com 2 2025-06-25 2026-05-26
staging-app.popsa.com 4 2026-05-16 2026-07-31
test-app.popsa.com 2 2026-04-08 2026-09-08
webapp.popsa.com 5 2026-04-28 2026-08-28
staging.webapp.popsa.com 4 2026-06-03 2026-10-06
promotions.staging.webapp.popsa.com 5 2026-04-25 2026-08-27
promotions.popsa.com 5 2026-04-25 2026-08-28
start.popsa.com 1 2026-09-22 2026-09-22
support.popsa.com 5 2026-04-21 2026-08-19
www.popsa.com 3 2026-06-10 2026-08-10

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