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 · 241 ms

HostCertsFirst seenLast seenDNS
firstintuition.co.uk 12 2025-07-09 2026-08-14 ok
mta-sts.firstintuition.co.uk 3 2025-10-16 2026-09-16 ok
www.firstintuition.co.uk 13 2025-07-09 2026-08-14 ok

Programmatic access, with DNS A records: API GET /v1/hosts/firstintuition.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/firstintuition.co.uk.