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 · 824 ms

HostCertsFirst seenLast seenDNS
happyhiller.com 6 2026-01-10 2026-08-27 ok
*.happyhiller.com 1 2026-01-10 2026-01-10 —
click.happyhiller.com 4 2026-05-01 2026-05-31 ok
ss.happyhiller.com 5 2026-05-05 2026-09-02 ok
load.ss.happyhiller.com 8 2026-04-22 2026-08-18 ok
dev.happyhiller.com 4 2026-04-16 2026-08-16 ok
www.happyhiller.com 5 2026-04-27 2026-08-27 ok
try.happyhiller.com 20 2026-05-05 2026-08-31 ok

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