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.

4 hosts · 265 ms

HostCertsFirst seenLast seenDNS
agcharter.org 14 2026-04-22 2026-08-19 ok
virtualtour.agcharter.org 5 2026-04-24 2026-08-23 ok
mta-sts.agcharter.org 3 2026-04-26 2026-09-15 ok
www.agcharter.org 10 2026-04-21 2026-08-17 ok

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