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.

6 hosts · 267 ms

HostCertsFirst seenLast seenDNS
gradian.co.uk 21 2026-05-04 2026-09-26 ok
*.gradian.co.uk 10 2026-01-05 2026-09-26 —
clicks.gradian.co.uk 5 2026-04-24 2026-08-22 ok
mta-sts.gradian.co.uk 1 2025-12-31 2025-12-31 ok
support.gradian.co.uk 11 2026-05-18 2026-09-13 ok
www.gradian.co.uk 10 2026-05-03 2026-08-30 ok

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