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.

12 hosts · 267 ms

HostCertsFirst seenLast seenDNS
betterworld.org 3 2026-02-06 2026-08-29 ok
*.betterworld.org 3 2026-02-06 2026-08-29 —
mb.betterworld.org 5 2026-05-25 2026-10-03 ok
d.betterworld.org 13 2026-05-23 2026-09-20 ok
load.d.betterworld.org 10 2026-05-13 2026-09-09 ok
email.betterworld.org 2 2025-07-18 2026-06-17 ok
help.betterworld.org 14 2026-06-01 2026-09-27 ok
calculator.betterworld.org 3 2026-06-12 2026-08-13 ok
docs.betterworld.org 16 2026-05-23 2026-09-18 ok
reports.betterworld.org 1 2026-09-30 2026-09-30 ok
support.betterworld.org 12 2026-04-22 2026-08-20 ok
try.betterworld.org 8 2026-04-23 2026-08-19 ok

Programmatic access, with DNS A records: API GET /v1/hosts/betterworld.org (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/betterworld.org.