Find every subdomain
of a domain.

Every hostname under a domain that ever appeared in a public TLS certificate — with certificate counts and first/last seen dates.

34 hosts · 252 ms

HostCertsFirst seenLast seen
on3.com 36 2026-04-24 2026-10-10
*.on3.com 11 2026-05-06 2026-09-01
67b51186e5d4c01746e72aa0.on3.com 6 2026-04-24 2026-08-20
*.dev2.on3.com 10 2026-05-06 2026-09-01
pea.on3.com 11 2026-06-01 2026-10-12
*.nonprod-qa.on3.com 16 2026-06-08 2026-10-04
origin.nonprod-qa.on3.com 2 2026-06-08 2026-07-05
*.origin.nonprod-qa.on3.com 2 2026-06-08 2026-07-05
*.qa.on3.com 10 2026-05-06 2026-09-01
origin.qa.on3.com 2 2025-10-04 2026-09-03
*.nonprod.on3.com 19 2026-06-08 2026-10-04
origin.nonprod.on3.com 1 2026-06-08 2026-06-08
*.origin.nonprod.on3.com 1 2026-06-08 2026-06-08
capig.on3.com 10 2026-05-17 2026-09-12
*.launch.on3.com 10 2026-05-06 2026-09-01
auth.on3.com 20 2026-04-18 2026-10-12
sli.on3.com 2 2026-04-11 2026-09-11
link.on3.com 5 2026-06-03 2026-10-01
*.transactional.on3.com 10 2026-05-06 2026-09-01
origin.on3.com 2 2025-10-04 2026-09-03
fbp.on3.com 3 2026-05-09 2026-08-25
*.newsletter.on3.com 10 2026-05-06 2026-09-01
docs.on3.com 4 2026-07-18 2026-09-15
*.docs.on3.com 4 2026-07-18 2026-09-15
recruits.on3.com 3 2026-07-06 2026-09-04
*.qa-east.on3.com 16 2026-06-14 2026-10-10
*.prod-east.on3.com 16 2026-06-14 2026-10-10
*.nonprod-dev.on3.com 16 2026-06-08 2026-10-04
origin.nonprod-dev.on3.com 2 2026-06-08 2026-07-05
*.origin.nonprod-dev.on3.com 2 2026-06-08 2026-07-05
*.dev.on3.com 10 2026-05-06 2026-09-01
link.dev.on3.com 4 2026-04-19 2026-08-17
recruits.dev.on3.com 2 2026-07-06 2026-07-06
*.spiny.on3.com 10 2026-05-06 2026-09-01

Programmatic access: API GET /v1/hosts/on3.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/on3.com.