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 · 234 ms

HostCertsFirst seenLast seen
emails.rakuten.com 2 2026-04-08 2026-04-09
*.emails.rakuten.com 2 2026-04-08 2026-04-09
brc.emails.rakuten.com 3 2026-06-04 2026-08-19
qa-brc.emails.rakuten.com 3 2026-06-04 2026-08-19
mi.emails.rakuten.com 2 2025-07-14 2026-06-13

Programmatic access: API GET /v1/hosts/emails.rakuten.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/emails.rakuten.com.