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 · 302 ms

HostCertsFirst seenLast seenDNS
unicol.com 31 2026-04-16 2026-10-02 ok
*.unicol.com 26 2026-04-16 2026-09-14 —
nac.unicol.com 5 2025-07-21 2026-08-22 ok
www.nac.unicol.com 5 2025-07-21 2026-08-22 nxdomain
middleware.unicol.com 6 2026-05-20 2026-09-17 ok
tracking.unicol.com 5 2026-05-10 2026-09-07 ok
ftp.unicol.com 4 2025-09-13 2026-09-14 ok
www.ftp.unicol.com 3 2025-09-13 2026-09-14 nxdomain
files.unicol.com 2 2026-06-24 2026-08-07 nxdomain
mta-sts.unicol.com 1 2025-12-31 2025-12-31 ok
www.unicol.com 6 2026-04-16 2026-08-12 ok

Programmatic access, with DNS A records: API GET /v1/hosts/unicol.com (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/unicol.com.