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.

10 hosts · 277 ms

HostCertsFirst seenLast seenDNS
discover-echo.com 6 2026-04-09 2026-08-05 ok
quote.discover-echo.com 10 2026-04-15 2026-08-12 ok
testimonial.discover-echo.com 10 2026-05-16 2026-09-11 ok
portal.discover-echo.com 3 2026-05-04 2026-08-03 ok
vpn.discover-echo.com 5 2026-03-17 2026-09-07 ok
www.vpn.discover-echo.com 5 2026-03-17 2026-09-07 nxdomain
dealers.discover-echo.com 3 2026-05-04 2026-08-03 ok
distributors.discover-echo.com 3 2026-05-04 2026-08-03 ok
dev.discover-echo.com 3 2026-05-04 2026-08-03 ok
www.discover-echo.com 12 2026-04-10 2026-08-06 ok

Programmatic access, with DNS A records: API GET /v1/hosts/discover-echo.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/discover-echo.com.