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 · 320 ms

HostCertsFirst seenLast seenDNS
rom.on.ca 6 2025-11-05 2026-09-12 ok
*.rom.on.ca 1 2025-11-05 2025-11-05 —
subscribe.rom.on.ca 4 2026-04-21 2026-08-18 ok
staging2.burgess-shale.rom.on.ca 5 2026-05-23 2026-09-19 ok
store.rom.on.ca 10 2026-05-24 2026-10-04 ok
staging2.cmhf.rom.on.ca 1 2026-08-31 2026-08-31 ok
www.staging2.cmhf.rom.on.ca 1 2026-08-31 2026-08-31 ok
shop.rom.on.ca 19 2026-05-23 2026-10-02 ok
www.rom.on.ca 5 2026-05-15 2026-09-12 ok
curiosity.rom.on.ca 5 2026-05-12 2026-09-05 ok
*.curiosity.rom.on.ca 5 2026-05-12 2026-09-05 —

Programmatic access, with DNS A records: API GET /v1/hosts/rom.on.ca (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/rom.on.ca.