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.

4 hosts · 272 ms

HostCertsFirst seenLast seenDNS
preferences.optimumrv.com 6 2026-04-26 2026-08-23 ok
Links.optimumrv.com 3 2025-09-29 2026-08-11 —
links.optimumrv.com 3 2025-09-16 2026-09-16 ok
www.links.optimumrv.com 3 2025-09-16 2026-09-16 nxdomain

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