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.

18 hosts · 320 ms

HostCertsFirst seenLast seenDNS
relaxium.com 15 2025-07-07 2026-09-23 ok
*.relaxium.com 11 2025-07-07 2026-09-12 —
video1.relaxium.com 5 2026-05-05 2026-09-04 ok
server1.relaxium.com 5 2026-06-05 2026-10-03 ok
staging2.relaxium.com 5 2026-04-25 2026-08-25 ok
server2.relaxium.com 4 2026-04-11 2026-08-11 ok
dashboard.relaxium.com 4 2026-04-15 2026-08-15 ok
staging.relaxium.com 5 2026-06-03 2026-10-03 ok
blogstaging.relaxium.com 4 2026-05-07 2026-07-07 ok
blog.relaxium.com 4 2026-06-03 2026-10-04 ok
deal.relaxium.com 3 2026-05-27 2026-08-09 ok
cpanel.relaxium.com 10 2026-06-14 2026-09-23 ok
go.relaxium.com 4 2026-05-07 2026-05-08 ok
help.relaxium.com 5 2026-05-14 2026-09-13 ok
shop.relaxium.com 7 2026-06-07 2026-08-26 ok
payment.relaxium.com 6 2026-05-02 2026-09-01 ok
support.relaxium.com 8 2026-04-15 2026-08-31 ok
www.relaxium.com 2 2026-06-24 2026-06-24 ok

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