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 · 280 ms

HostCertsFirst seenLast seenDNS
hssv.org 12 2026-05-30 2026-09-25 ok
secure.hssv.org 5 2026-05-12 2026-09-09 ok
donate.hssv.org 5 2026-05-12 2026-09-09 nxdomain
give.hssv.org 11 2026-05-21 2026-09-16 ok
form.hssv.org 10 2026-04-28 2026-09-25 ok
intranet.hssv.org 16 2026-06-05 2026-10-02 ok
www.hssv.org 12 2026-05-29 2026-09-25 ok

Programmatic access, with DNS A records: API GET /v1/hosts/hssv.org (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/hssv.org.