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.

9 hosts · 318 ms

HostCertsFirst seenLast seenDNS
alison.com 20 2026-03-04 2026-09-27 ok
*.alison.com 20 2026-03-04 2026-09-27 —
connect-hub.alison.com 1 2026-08-26 2026-08-26 ok
merch.alison.com 3 2026-06-18 2026-08-16 ok
emulator.alison.com 3 2026-07-15 2026-09-22 ok
design-emulator.alison.com 3 2026-09-22 2026-09-22 ok
adsconsent.alison.com 5 2026-05-12 2026-09-03 ok
dev.alison.com 1 2025-10-30 2025-10-30 nodata
*.dev.alison.com 1 2025-10-30 2025-10-30 —

Programmatic access, with DNS A records: API GET /v1/hosts/alison.com (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/alison.com.