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.

10 hosts · 292 ms

HostCertsFirst seenLast seenDNS
freetaxusa.com 27 2026-01-08 2026-09-11 ok
*.freetaxusa.com 25 2026-01-08 2026-09-11 —
send1.freetaxusa.com 5 2026-05-03 2026-08-31 ok
tokenize.freetaxusa.com 1 2026-05-05 2026-05-05 ok
sandboxtokenize.freetaxusa.com 1 2026-05-05 2026-05-05 ok
tpg.freetaxusa.com 1 2026-02-12 2026-02-12 nxdomain
sbtpg.freetaxusa.com 1 2026-02-12 2026-02-12 ok
links.support.freetaxusa.com 5 2026-05-17 2026-09-14 ok
www.freetaxusa.com 2 2026-01-10 2026-01-10 ok
community.freetaxusa.com 12 2026-05-12 2026-09-07 ok

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