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.

9 hosts · 267 ms

HostCertsFirst seenLast seen
aeroplan.com 11 2025-07-10 2026-08-18
*.aeroplan.com 10 2025-07-10 2026-08-06
uat1.toptier.aeroplan.com 10 2025-07-10 2026-08-06
int1.toptier.aeroplan.com 10 2025-07-10 2026-08-06
ecss.aeroplan.com 1 2025-08-08 2025-08-08
www.ecss.aeroplan.com 1 2025-08-08 2025-08-08
cs-rt.aeroplan.com 1 2025-08-08 2025-08-08
www.cs-rt.aeroplan.com 1 2025-08-08 2025-08-08
*.tst.aeroplan.com 10 2025-07-10 2026-08-06

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