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.

6 hosts · 320 ms

HostCertsFirst seenLast seenDNS
iatse728.org 12 2025-09-23 2026-09-20 ok
*.iatse728.org 12 2025-09-23 2026-09-20 —
trainingvpn.iatse728.org 1 2026-02-03 2026-02-03 ok
www.trainingvpn.iatse728.org 1 2026-02-03 2026-02-03 nxdomain
assets.iatse728.org 2 2026-02-22 2026-07-10 ok
mta-sts.iatse728.org 4 2026-04-18 2026-08-16 ok

Programmatic access, with DNS A records: API GET /v1/hosts/iatse728.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/iatse728.org.