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.

7 hosts · 318 ms

HostCertsFirst seenLast seenDNS
ox.io 9 2025-11-11 2026-09-18 ok
*.ox.io 1 2025-11-11 2025-11-11 —
blog.ox.io 8 2026-07-22 2026-09-19 ok
email.ox.io 7 2026-07-22 2026-09-19 ok
glam.ox.io 1 2026-08-27 2026-08-27 ok
info.ox.io 8 2026-07-22 2026-09-19 ok
www.ox.io 6 2026-07-21 2026-09-18 ok

Programmatic access, with DNS A records: API GET /v1/hosts/ox.io (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/ox.io.