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.

14 hosts · 349 ms

HostCertsFirst seenLast seenDNS
rythmia.com 23 2026-04-15 2026-09-18 ok
*.rythmia.com 12 2026-04-15 2026-09-18 —
data.rythmia.com 14 2026-05-21 2026-09-17 ok
gtm.azure.rythmia.com 3 2026-02-20 2026-10-05 ok
preview.azure.rythmia.com 4 2026-02-20 2026-10-05 ok
staff.rythmia.com 4 2026-04-17 2026-08-20 ok
bimi.rythmia.com 2 2026-08-17 2026-08-17 ok
email.rythmia.com 4 2026-04-17 2026-08-15 ok
info.rythmia.com 7 2026-05-22 2026-09-18 ok
promo.rythmia.com 9 2026-04-21 2026-10-03 ok
llp.rythmia.com 20 2026-05-24 2026-09-20 ok
files.rythmia.com 9 2026-05-30 2026-09-26 ok
www.rythmia.com 10 2026-05-06 2026-09-01 ok
safety.rythmia.com 4 2026-04-17 2026-08-21 ok

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