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.

8 hosts · 184 ms

HostCertsFirst seenLast seen
rppm.com 13 2026-05-31 2026-09-26
base.rppm.com 7 2026-05-01 2026-09-11
clientportal.rppm.com 6 2026-05-05 2026-08-31
login.rppm.com 10 2026-05-08 2026-09-03
mta-sts.rppm.com 4 2026-04-19 2026-08-16
client-aristocrat.rppm.com 1 2025-11-03 2025-11-03
www.rppm.com 11 2026-06-01 2026-09-27
acadamy.rppm.com 13 2026-06-02 2026-09-28

Programmatic access: API GET /v1/hosts/rppm.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/rppm.com.