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.

8 hosts · 227 ms

HostCertsFirst seenLast seenDNS
campion.com 5 2026-01-19 2026-09-22 ok
*.campion.com 4 2026-07-25 2026-09-22 —
w25.campion.com 2 2026-05-10 2026-05-10 ok
sync.campion.com 6 2026-05-31 2026-10-01 ok
chat-staging.campion.com 1 2026-10-01 2026-10-01 nodata
tst.campion.com 4 2026-04-13 2026-08-13 ok
chat-dev.campion.com 1 2026-10-01 2026-10-01 nodata
www.campion.com 1 2026-01-19 2026-01-19 ok

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