Find every subdomain
of a domain.

Every hostname under a domain that ever appeared in a public TLS certificate — with certificate counts and first/last seen dates.

5 hosts · 288 ms

HostCertsFirst seenLast seen
firststars.com 13 2026-04-26 2026-08-22
shopping.firststars.com 10 2026-04-17 2026-08-14
n8n.firststars.com 5 2026-04-27 2026-08-24
mta-sts.firststars.com 5 2026-05-26 2026-09-23
www.firststars.com 8 2026-04-26 2026-08-22

Programmatic access: API GET /v1/hosts/firststars.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/firststars.com.