Find every subdomain
of a domain.

Every hostname under a domain that ever appeared in a public TLS certificate — with certificate counts and first/last seen dates.

5 hosts · 198 ms

HostCertsFirst seenLast seen
tccf.tw 8 2026-03-02 2026-09-05
*.tccf.tw 8 2026-03-02 2026-09-05
tccf-stage-api.tccf.tw 3 2026-06-26 2026-08-25
tccf-api.tccf.tw 2 2025-07-23 2026-06-23
tccf-api-backup.tccf.tw 2 2025-08-10 2026-07-11

Programmatic access: API GET /v1/hosts/tccf.tw (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/tccf.tw.