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.

13 hosts · 387 ms

HostCertsFirst seenLast seenDNS
m-x.ca 9 2025-10-27 2026-09-27 ok
*.m-x.ca 8 2025-10-27 2026-09-27 —
*.qa.m-x.ca 8 2025-10-27 2026-09-27 —
mailsub.m-x.ca 5 2026-05-03 2026-08-31 ok
forward.m-x.ca 5 2026-05-18 2026-09-21 ok
*.staging.m-x.ca 8 2025-10-27 2026-09-27 —
app.m-x.ca 20 2026-05-16 2026-09-11 ok
mailer.m-x.ca 5 2026-05-18 2026-09-21 ok
rules.m-x.ca 5 2026-05-14 2026-09-11 ok
concoursoptions.m-x.ca 16 2026-05-28 2026-09-23 ok
mxrconnect.m-x.ca 1 2026-04-16 2026-04-16 ok
optionscontest.m-x.ca 14 2026-05-26 2026-09-22 ok
*.dev.m-x.ca 8 2025-10-27 2026-09-27 —

Programmatic access, with DNS A records: API GET /v1/hosts/m-x.ca (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/m-x.ca.