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 · 329 ms

HostCertsFirst seenLast seenDNS
cloud.mail.seur.info 2 2026-08-28 2026-08-28 ok
image.mail.seur.info 3 2026-01-21 2026-09-07 ok
click.mail.seur.info 1 2026-02-06 2026-02-06 ok
view.mail.seur.info 1 2026-02-06 2026-02-06 ok

Programmatic access, with DNS A records: API GET /v1/hosts/seur.info (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/seur.info.