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.

16 hosts · 556 ms

HostCertsFirst seenLast seenDNS
rsplgroup.com 2 2025-07-08 2026-08-06 ok
hec.rsplgroup.com 2 2026-02-21 2026-02-24 nxdomain
*.hec.rsplgroup.com 2 2026-02-21 2026-02-24 —
wecare.rsplgroup.com 3 2025-08-13 2026-08-14 ok
www.wecare.rsplgroup.com 3 2025-08-13 2026-08-14 nxdomain
scan2sure.rsplgroup.com 1 2026-05-28 2026-05-28 ok
www.scan2sure.rsplgroup.com 1 2026-05-28 2026-05-28 nxdomain
s2sapi.rsplgroup.com 1 2025-11-19 2025-11-19 ok
www.s2sapi.rsplgroup.com 1 2025-11-19 2025-11-19 nxdomain
itservicedesk.rsplgroup.com 49 2026-04-13 2026-08-13 ok
crm.rsplgroup.com 10 2026-05-03 2026-08-30 ok
dlp.rsplgroup.com 1 2025-09-05 2025-09-05 ok
www.dlp.rsplgroup.com 1 2025-09-05 2025-09-05 nxdomain
adfs.rsplgroup.com 1 2026-05-13 2026-05-13 ok
www.adfs.rsplgroup.com 1 2026-05-13 2026-05-13 nxdomain
www.rsplgroup.com 2 2025-07-08 2026-08-06 ok

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