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 · 343 ms

HostCertsFirst seenLast seenDNS
synax.ch 45 2026-04-18 2026-09-18 ok
*.synax.ch 40 2026-04-18 2026-09-18 —
www.synax.ch 4 2026-04-19 2026-08-13 ok

Programmatic access, with DNS A records: API GET /v1/hosts/synax.ch (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/synax.ch.