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.

11 hosts · 291 ms

HostCertsFirst seenLast seenDNS
vapormed.com 5 2026-04-22 2026-08-20 ok
b2b.vapormed.com 5 2026-04-22 2026-08-20 ok
mcstaging-b2b.vapormed.com 5 2026-05-08 2026-09-05 ok
mailing.b2b.vapormed.com 2 2025-07-21 2026-07-28 ok
www.mailing.b2b.vapormed.com 2 2025-07-21 2026-07-28 ok
mcstaging.vapormed.com 5 2026-05-08 2026-09-05 ok
mailing.vapormed.com 1 2025-07-21 2025-07-21 nodata
web.mailing.vapormed.com 1 2025-07-21 2025-07-21 nxdomain
www.mailing.vapormed.com 1 2025-07-21 2025-07-21 nxdomain
mail.vapormed.com 2 2026-03-02 2026-08-10 ok
www.vapormed.com 5 2026-04-22 2026-08-20 ok

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