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 · 313 ms

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HostCertsFirst seenLast seen
importantnotimportant.com 14 2026-06-03 2026-10-05
*.importantnotimportant.com 14 2026-06-03 2026-10-05
shop.importantnotimportant.com 13 2026-04-23 2026-08-31
podcast.importantnotimportant.com 1 2026-04-19 2026-04-19
www.importantnotimportant.com 8 2026-05-07 2026-09-02

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