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 · 288 ms

HostCertsFirst seenLast seenDNS
jsmf.org 25 2026-05-12 2026-09-27 ok
*.jsmf.org 13 2026-05-12 2026-09-27 —
tal.jsmf.org 4 2026-05-18 2026-05-18 ok
grants.jsmf.org 16 2026-05-06 2026-09-01 ok
mta-sts.jsmf.org 1 2026-09-03 2026-09-03 ok
www.jsmf.org 10 2026-05-19 2026-09-14 ok

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