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.

3 hosts · 208 ms

HostCertsFirst seenLast seen
reiku.de 6 2026-05-10 2026-09-05
*.reiku.de 1 2026-06-14 2026-06-14
www.reiku.de 5 2026-05-10 2026-09-05

Programmatic access: API GET /v1/hosts/reiku.de (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/reiku.de.