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.

4 hosts · 303 ms

HostCertsFirst seenLast seenDNS
cloud.email.nasiumtraining.com 5 2026-03-25 2026-08-31 ok
image.email.nasiumtraining.com 29 2026-03-25 2026-09-18 ok
click.email.nasiumtraining.com 5 2026-03-25 2026-08-26 ok
view.email.nasiumtraining.com 3 2026-03-25 2026-08-26 ok

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