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 · 207 ms

HostCertsFirst seenLast seen
cloud.communication.riu.com 4 2025-06-14 2026-06-03
image.communication.riu.com 4 2026-04-13 2026-09-13
click.communication.riu.com 3 2025-06-14 2026-07-12
view.communication.riu.com 3 2025-06-14 2026-07-12

Programmatic access: API GET /v1/hosts/communication.riu.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/communication.riu.com.