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.

4 hosts · 215 ms

HostCertsFirst seenLast seenDNS
tracking.connect.columbiabank.com 5 2026-06-16 2026-08-25 ok
pages.connect.columbiabank.com 5 2026-06-16 2026-08-25 ok
files.connect.columbiabank.com 4 2026-05-22 2026-07-31 ok
links.connect.columbiabank.com 5 2026-06-16 2026-08-25 ok

Programmatic access, with DNS A records: API GET /v1/hosts/connect.columbiabank.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/connect.columbiabank.com.