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 · 248 ms

HostCertsFirst seenLast seenDNS
springmarket-email.com 7 2026-04-12 2026-09-10 ok
staging.springmarket-email.com 6 2026-05-04 2026-09-11 ok
www.staging.springmarket-email.com 7 2026-06-18 2026-09-18 ok
testing.springmarket-email.com 3 2026-08-20 2026-10-01 ok
www.testing.springmarket-email.com 1 2026-09-09 2026-09-09 ok
api.springmarket-email.com 6 2026-04-23 2026-09-10 ok
www.api.springmarket-email.com 5 2026-06-18 2026-09-19 ok
m.springmarket-email.com 8 2026-04-13 2026-09-22 ok
www.m.springmarket-email.com 6 2026-06-18 2026-09-26 ok
cdn.springmarket-email.com 5 2026-05-06 2026-09-27 ok
www.cdn.springmarket-email.com 5 2026-06-22 2026-09-22 ok
app.springmarket-email.com 8 2026-04-15 2026-09-14 ok
www.app.springmarket-email.com 6 2026-06-17 2026-09-15 ok
mta-sts.springmarket-email.com 8 2026-04-15 2026-09-14 ok
www.mta-sts.springmarket-email.com 6 2026-06-18 2026-09-14 ok
test.springmarket-email.com 7 2026-05-11 2026-09-17 ok
www.test.springmarket-email.com 4 2026-06-17 2026-08-13 ok
www.springmarket-email.com 7 2026-04-21 2026-09-09 ok

Programmatic access, with DNS A records: API GET /v1/hosts/springmarket-email.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/springmarket-email.com.