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.

10 hosts · 318 ms

HostCertsFirst seenLast seen
particleformen.com 8 2026-04-19 2026-08-15
wd.particleformen.com 13 2026-06-04 2026-10-01
tracking.particleformen.com 5 2026-07-27 2026-09-25
i.particleformen.com 4 2026-05-30 2026-09-17
shop.particleformen.com 5 2026-06-03 2026-10-04
tracker.particleformen.com 5 2026-07-15 2026-09-24
ss.particleformen.com 5 2026-04-24 2026-10-02
dev.particleformen.com 18 2026-04-17 2026-10-11
www.particleformen.com 10 2026-04-18 2026-08-14
quiz.particleformen.com 3 2026-05-11 2026-09-08

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