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.

5 hosts · 254 ms

HostCertsFirst seenLast seen
swappa.com 21 2025-09-15 2026-10-03
*.swappa.com 20 2026-05-22 2026-10-03
dev.swappa.com 1 2026-06-29 2026-06-29
www.dev.swappa.com 1 2026-06-29 2026-06-29
www.swappa.com 1 2025-09-15 2025-09-15

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