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.

23 hosts · 178 ms

HostCertsFirst seenLast seen
b21.ifly.southwest.com 3 2026-06-07 2026-08-22
m21.ifly.southwest.com 2 2025-10-07 2026-09-07
res21.ifly.southwest.com 2 2025-10-07 2026-09-07
t21.ifly.southwest.com 2 2025-10-07 2026-09-07
b22.ifly.southwest.com 3 2026-06-07 2026-08-22
m22.ifly.southwest.com 2 2025-10-07 2026-09-07
res22.ifly.southwest.com 2 2025-10-07 2026-09-07
t22.ifly.southwest.com 2 2025-10-07 2026-09-07
b23.ifly.southwest.com 3 2026-06-07 2026-08-22
m23.ifly.southwest.com 2 2025-10-07 2026-09-07
res23.ifly.southwest.com 2 2025-10-07 2026-09-07
t23.ifly.southwest.com 2 2025-10-07 2026-09-07
b24.ifly.southwest.com 3 2026-06-07 2026-08-22
m24.ifly.southwest.com 2 2025-10-07 2026-09-07
res24.ifly.southwest.com 2 2025-10-07 2026-09-07
t24.ifly.southwest.com 2 2025-10-07 2026-09-07
m18.ifly.southwest.com 2 2025-10-07 2026-09-07
res18.ifly.southwest.com 2 2025-10-07 2026-09-07
t18.ifly.southwest.com 2 2025-10-07 2026-09-07
b.ifly.southwest.com 3 2026-06-25 2026-09-10
m.ifly.southwest.com 2 2025-10-07 2026-09-07
res.ifly.southwest.com 2 2025-10-07 2026-09-07
t.ifly.southwest.com 2 2025-10-07 2026-09-07

Programmatic access: API GET /v1/hosts/ifly.southwest.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/ifly.southwest.com.