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 · 277 ms

HostCertsFirst seenLast seenDNS
transaxio.fr 6 2026-05-27 2026-09-20 ok
enterpriseregistration.transaxio.fr 2 2025-11-19 2026-06-08 ok
mta-sts.transaxio.fr 5 2026-05-23 2026-09-20 ok
www.transaxio.fr 6 2026-05-27 2026-09-20 ok

Programmatic access, with DNS A records: API GET /v1/hosts/transaxio.fr (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/transaxio.fr.