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.

6 hosts · 248 ms

HostCertsFirst seenLast seenDNS
troutroutes.com 4 2025-08-27 2026-09-03 ok
auth.troutroutes.com 3 2026-06-05 2026-10-02 ok
clicks.troutroutes.com 3 2026-05-13 2026-08-27 ok
maps.troutroutes.com 4 2026-04-11 2026-08-09 ok
www.troutroutes.com 3 2026-04-29 2026-08-31 ok
try.troutroutes.com 12 2026-04-20 2026-08-16 ok

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