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.

5 hosts · 215 ms

HostCertsFirst seenLast seenDNS
singlewiresoftware.com 7 2025-08-07 2026-09-03 ok
*.singlewiresoftware.com 5 2026-04-27 2026-09-03 —
hello.singlewiresoftware.com 4 2026-06-05 2026-08-11 ok
visit.singlewiresoftware.com 10 2026-04-24 2026-09-21 ok
www.singlewiresoftware.com 2 2025-08-07 2026-07-08 ok

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