Find every subdomain
of a domain.

Every hostname under a domain that ever appeared in a public TLS certificate — with certificate counts, first/last seen and live DNS status.

7 hosts · 308 ms

HostCertsFirst seenLast seenDNS
traveldefenders.com 6 2025-09-24 2026-09-24 ok
*.traveldefenders.com 1 2025-09-24 2025-09-24 —
quote.traveldefenders.com 3 2025-09-30 2026-08-31 ok
dev.quote.traveldefenders.com 3 2025-09-24 2026-02-02 ok
staging.traveldefenders.com 6 2026-04-30 2026-09-01 ok
trk.traveldefenders.com 2 2026-08-10 2026-08-10 ok
www.traveldefenders.com 5 2026-05-21 2026-09-21 ok

Programmatic access, with DNS A records: API GET /v1/hosts/traveldefenders.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/traveldefenders.com.