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 · 284 ms

HostCertsFirst seenLast seen
cloud.breathe.lumen.me 2 2026-04-24 2026-09-25
image.breathe.lumen.me 2 2026-01-05 2026-05-21
click.breathe.lumen.me 3 2026-04-24 2026-09-25
view.breathe.lumen.me 2 2026-04-24 2026-09-28

Programmatic access: API GET /v1/hosts/breathe.lumen.me (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/breathe.lumen.me.