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.

9 hosts · 236 ms

HostCertsFirst seenLast seenDNS
express1040.com 23 2026-01-08 2026-09-11 ok
*.express1040.com 21 2026-01-08 2026-09-11 —
send1.express1040.com 5 2026-04-23 2026-08-24 ok
tokenize.express1040.com 1 2026-05-05 2026-05-05 ok
sandboxtokenize.express1040.com 1 2026-05-05 2026-05-05 ok
tpg.express1040.com 1 2026-02-12 2026-02-12 nxdomain
sbtpg.express1040.com 1 2026-02-12 2026-02-12 ok
links.express1040.com 5 2026-05-01 2026-08-29 ok
www.express1040.com 2 2026-01-10 2026-01-10 ok

Programmatic access, with DNS A records: API GET /v1/hosts/express1040.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/express1040.com.