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.

11 hosts · 264 ms

HostCertsFirst seenLast seenDNS
roberthalf.jp 1 2026-01-28 2026-01-28 ok
*.roberthalf.jp 1 2026-01-28 2026-01-28 —
employee.roberthalf.jp 2 2025-07-18 2026-06-18 ok
int-employee.roberthalf.jp 2 2025-07-03 2026-06-03 ok
contractor.roberthalf.jp 5 2025-07-03 2026-06-03 ok
int-contractor.roberthalf.jp 2 2025-07-03 2026-06-03 ok
tags.roberthalf.jp 2 2025-07-02 2026-06-02 ok
collect.roberthalf.jp 2 2025-07-02 2026-06-02 ok
dev.roberthalf.jp 5 2025-06-12 2026-05-27 nodata
ordia.dev.roberthalf.jp 4 2025-07-03 2026-06-03 ok
int-ordia.dev.roberthalf.jp 2 2025-08-06 2026-07-07 ok

Programmatic access, with DNS A records: API GET /v1/hosts/roberthalf.jp (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/roberthalf.jp.