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.

6 hosts · 355 ms

HostCertsFirst seenLast seenDNS
rosyblue.com 5 2025-12-04 2026-09-17 nodata
api.rosyblue.com 4 2026-03-26 2026-09-14 ok
jde-dv.rosyblue.com 1 2026-09-17 2026-09-17 ok
api-dv.rosyblue.com 2 2026-02-28 2026-07-23 ok
www.rosyblue.com 3 2025-12-04 2025-12-04 nxdomain
api-py.rosyblue.com 3 2026-03-18 2026-09-07 ok

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