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.

4 hosts · 236 ms

HostCertsFirst seenLast seen
squareadvance.com 13 2026-04-22 2026-08-20
contracts.squareadvance.com 4 2026-04-15 2026-08-13
mta-sts.squareadvance.com 1 2025-11-18 2025-11-18
www.squareadvance.com 8 2026-04-22 2026-08-20

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