Find every subdomain
of a domain.

Every hostname under a domain that ever appeared in a public TLS certificate — with certificate counts, first/last seen and live DNS status.

11 hosts · 323 ms

HostCertsFirst seenLast seenDNS
river.com 5 2026-04-12 2026-09-24 ok
irs-client-id.river.com 1 2025-12-01 2025-12-01 nodata
api.platform.river.com 5 2026-05-21 2026-09-18 ok
admin.river.com 6 2026-04-08 2026-09-18 ok
subscription.river.com 6 2026-05-12 2026-09-07 ok
partner.river.com 9 2026-04-27 2026-08-24 ok
status.river.com 4 2026-04-11 2026-08-08 ok
support.river.com 6 2025-06-18 2026-09-14 ok
trust.river.com 11 2026-05-24 2026-09-19 ok
www.river.com 5 2026-04-12 2026-09-24 ok
verify.river.com 1 2025-12-02 2025-12-02 ok

Programmatic access, with DNS A records: API GET /v1/hosts/river.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/river.com.