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.

3 hosts · 390 ms

HostCertsFirst seenLast seenDNS
open.emails.piedmontng.com 2 2025-07-23 2026-07-14 ok
links.emails.piedmontng.com 2 2025-07-23 2026-07-14 ok
content.emails.piedmontng.com 2 2025-07-23 2026-07-14 ok

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