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.

5 hosts · 223 ms

HostCertsFirst seenLast seenDNS
fluxon.com 12 2026-05-08 2026-10-05 ok
*.fluxon.com 7 2026-05-17 2026-09-12 —
content.fluxon.com 3 2026-05-13 2026-09-01 ok
static-content.fluxon.com 3 2026-05-13 2026-08-31 ok
www.fluxon.com 5 2026-05-08 2026-10-05 ok

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