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 · 274 ms

HostCertsFirst seenLast seenDNS
*.sompo-ict.co.uk 4 2025-11-14 2026-08-31 —
genai-workshop-202510.sompo-ict.co.uk 1 2025-10-01 2025-10-01 nxdomain
genai-workshop.sompo-ict.co.uk 1 2026-05-15 2026-05-15 nxdomain
mta-sts.sompo-ict.co.uk 2 2026-06-12 2026-08-22 ok

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