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.

8 hosts · 272 ms

HostCertsFirst seenLast seenDNS
world-first.co.uk 1 2026-05-02 2026-05-02 ok
*.world-first.co.uk 1 2026-05-02 2026-05-02 —
e.world-first.co.uk 31 2026-05-28 2026-10-05 ok
*.e.world-first.co.uk 18 2026-06-07 2026-10-05 —
service.world-first.co.uk 31 2026-04-23 2026-10-03 ok
*.service.world-first.co.uk 20 2026-04-23 2026-10-03 —
secure.world-first.co.uk 9 2026-04-27 2026-09-01 ok
www.secure.world-first.co.uk 1 2026-06-11 2026-06-11 ok

Programmatic access, with DNS A records: API GET /v1/hosts/world-first.co.uk (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/world-first.co.uk.