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 · 199 ms

HostCertsFirst seenLast seen
cloud.em.riotgames.com 1 2025-08-05 2025-08-05
image.em.riotgames.com 1 2026-01-21 2026-01-21
click.em.riotgames.com 1 2025-07-31 2025-07-31
view.em.riotgames.com 1 2025-08-05 2025-08-05

Programmatic access: API GET /v1/hosts/em.riotgames.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/em.riotgames.com.