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.

3 hosts · 274 ms

HostCertsFirst seenLast seenDNS
nicmanager.email 1 2026-05-07 2026-05-07 ok
mta-sts.nicmanager.email 4 2026-06-05 2026-10-03 ok
www.nicmanager.email 1 2026-05-07 2026-05-07 nodata

Programmatic access, with DNS A records: API GET /v1/hosts/nicmanager.email (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/nicmanager.email.