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.

14 hosts · 287 ms

HostCertsFirst seenLast seenDNS
gi.org 4 2025-09-24 2025-10-14 ok
*.gi.org 5 2025-09-24 2025-10-31 —
go.gi.org 4 2026-05-23 2026-07-30 ok
pop.gi.org 4 2026-04-22 2026-04-22 ok
prototypes.gi.org 6 2026-05-03 2026-09-02 ok
acgmeetings.gi.org 16 2026-05-19 2026-09-15 ok
www.acgmeetings.gi.org 12 2026-04-27 2026-08-24 ok
jenkins.gi.org 5 2026-05-15 2026-09-12 ok
patients.gi.org 4 2026-05-05 2026-05-05 ok
www.sat.gi.org 2 2025-09-12 2026-08-13 ok
fthr-content.gi.org 4 2026-04-19 2026-08-16 ok
listserv.gi.org 4 2025-09-24 2025-10-14 ok
industry.gi.org 17 2026-05-11 2026-09-24 ok
www.industry.gi.org 27 2026-04-20 2026-10-04 ok

Programmatic access, with DNS A records: API GET /v1/hosts/gi.org (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/gi.org.