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.

5 hosts · 319 ms

HostCertsFirst seenLast seenDNS
transficc.com 35 2026-05-10 2026-09-30 ok
*.transficc.com 20 2026-05-20 2026-09-15 —
mta-sts.transficc.com 18 2026-05-10 2026-09-06 ok
trust.transficc.com 9 2026-05-30 2026-09-25 ok
www.transficc.com 5 2026-06-01 2026-09-30 ok

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