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 · 290 ms

HostCertsFirst seenLast seenDNS
bstn.com 4 2025-09-03 2026-09-18 ok
*.bstn.com 4 2025-09-03 2026-09-18 —
2893409274.bstn.com 11 2026-06-01 2026-09-27 ok
ffvpn.bstn.com 5 2026-04-26 2026-08-24 ok
jobs.bstn.com 3 2026-06-05 2026-08-14 ok
www.jobs.bstn.com 3 2026-06-05 2026-08-14 ok
news.bstn.com 10 2026-05-23 2026-09-18 ok

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