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.

85 hosts · 470 ms

HostCertsFirst seenLast seenDNS
cruciallearning.com 5 2026-05-02 2026-09-03 ok
*.cruciallearning.com 2 2026-07-02 2026-07-02 —
api2.cruciallearning.com 1 2026-01-23 2026-01-23 ok
qa-api2.cruciallearning.com 1 2026-01-23 2026-01-23 ok
dev-api2.cruciallearning.com 1 2026-01-14 2026-01-14 ok
dev-api-alt2.cruciallearning.com 1 2026-07-16 2026-07-16 nxdomain
dev-platform-alt2.cruciallearning.com 1 2026-07-16 2026-07-16 nodata
dev-cdn-alt2.cruciallearning.com 1 2026-07-16 2026-07-16 nxdomain
dev-socket-alt2.cruciallearning.com 1 2026-07-16 2026-07-16 nxdomain
dev-delivery-alt2.cruciallearning.com 1 2026-07-16 2026-07-16 nxdomain
da.cruciallearning.com 18 2026-05-23 2026-09-18 ok
preprod.cruciallearning.com 5 2026-05-10 2026-09-11 ok
itservice.cruciallearning.com 1 2026-06-30 2026-06-30 ok
udl-stage.cruciallearning.com 2 2026-08-04 2026-08-04 servfail
auth.cruciallearning.com 10 2026-05-01 2026-08-28 ok
qa-auth.cruciallearning.com 10 2026-04-29 2026-08-26 ok
dev-auth.cruciallearning.com 10 2026-04-29 2026-08-27 ok
sdi.cruciallearning.com 2 2025-08-29 2026-07-30 ok
core-cloud.auth.sandbox.uk.sdi.cruciallearning.com 4 2025-07-07 2025-08-05 nxdomain
cdn-ms-qa.qa.us.sdi.cruciallearning.com 3 2025-10-19 2026-09-19 ok
cdn-ms.qa.us.sdi.cruciallearning.com 3 2025-10-19 2026-09-19 ok
cdn-ms-prod.prod.us.sdi.cruciallearning.com 3 2025-10-21 2026-09-21 ok
cdn-ms.prod.us.sdi.cruciallearning.com 3 2025-10-21 2026-09-21 ok
core-cloud.auth.dev-alt.us.sdi.cruciallearning.com 2 2025-07-07 2025-07-22 servfail
admin.dev-alt.us.sdi.cruciallearning.com 4 2025-07-07 2025-09-16 servfail
core-cloud-dev-alt.cognito.dev-alt.us.sdi.cruciallearning.com 1 2025-09-16 2025-09-16 servfail
app.dev-alt.us.sdi.cruciallearning.com 4 2025-07-07 2025-09-16 servfail
core-cloud1-dev-alt.dev-alt.us.sdi.cruciallearning.com 5 2025-09-17 2025-09-23 servfail
core-cloud-dev-alt.dev-alt.us.sdi.cruciallearning.com 5 2025-07-10 2025-07-30 servfail
cdn-admin-dev-alt.dev-alt.us.sdi.cruciallearning.com 4 2025-07-07 2025-09-16 servfail
cdn-app-dev-alt.dev-alt.us.sdi.cruciallearning.com 4 2025-07-07 2025-09-16 servfail
cdn-ms.dev.us.sdi.cruciallearning.com 2 2025-10-19 2026-09-19 ok
cdn-ms-dev.dev.us.sdi.cruciallearning.com 2 2025-10-19 2026-09-19 ok
cdn-ms.sandbox.us.sdi.cruciallearning.com 2 2025-10-29 2026-09-29 ok
cdn-ms-sandbox.sandbox.us.sdi.cruciallearning.com 2 2025-10-29 2026-09-29 ok
api.cruciallearning.com 3 2025-06-15 2026-08-18 ok
qa-api.cruciallearning.com 3 2026-04-26 2026-09-26 ok
dev-api.cruciallearning.com 3 2025-06-15 2026-08-18 ok
link.cruciallearning.com 5 2026-05-16 2026-09-13 ok
servicedesk.cruciallearning.com 1 2026-04-29 2026-04-29 nxdomain
mktoemail.cruciallearning.com 14 2026-04-12 2026-10-06 ok
classroom.cruciallearning.com 3 2025-09-22 2026-08-23 ok
qa-classroom.cruciallearning.com 2 2026-03-12 2026-07-28 ok
dev-classroom.cruciallearning.com 2 2026-03-15 2026-08-15 ok
platform.cruciallearning.com 3 2025-06-15 2026-08-18 ok
qa-platform.cruciallearning.com 3 2026-04-26 2026-09-26 ok
dev-platform.cruciallearning.com 3 2025-06-15 2026-08-18 ok
cdn.cruciallearning.com 2 2025-12-24 2026-08-18 ok
qa-cdn.cruciallearning.com 2 2025-12-15 2026-08-18 ok
dev-cdn.cruciallearning.com 2 2025-11-30 2026-08-18 ok
sdi-admin.cruciallearning.com 1 2026-01-15 2026-01-15 ok
udl-dev-vpn.cruciallearning.com 2 2026-05-26 2026-05-26 nxdomain
go.cruciallearning.com 10 2026-05-04 2026-08-30 ok
help.cruciallearning.com 4 2025-08-13 2026-08-28 ok
www.help.cruciallearning.com 1 2025-08-13 2025-08-13 nxdomain
webinars.cruciallearning.com 3 2026-05-18 2026-10-01 ok
producers.cruciallearning.com 5 2025-09-17 2026-08-28 ok
trainers.cruciallearning.com 4 2025-08-05 2026-08-28 ok
www.trainers.cruciallearning.com 1 2025-08-05 2025-08-05 nxdomain
socket.cruciallearning.com 41 2025-06-18 2026-09-30 ok
qa-socket.cruciallearning.com 5 2026-02-09 2026-09-26 ok
dev-socket.cruciallearning.com 4 2025-11-25 2026-08-18 ok
sandbox-socket.cruciallearning.com 2 2026-08-01 2026-08-01 ok
*.sandbox-socket.cruciallearning.com 2 2026-08-01 2026-08-01 —
qa-api-alt.cruciallearning.com 2 2026-07-08 2026-07-09 nodata
dev-api-alt.cruciallearning.com 1 2025-12-03 2025-12-03 ok
qa-platform-alt.cruciallearning.com 2 2026-07-08 2026-07-09 ok
dev-platform-alt.cruciallearning.com 2 2025-12-03 2026-05-28 ok
qa-cdn-alt.cruciallearning.com 2 2026-07-08 2026-07-09 nodata
dev-cdn-alt.cruciallearning.com 1 2025-12-03 2025-12-03 ok
qa-socket-alt.cruciallearning.com 2 2026-07-08 2026-07-09 nodata
dev-socket-alt.cruciallearning.com 8 2025-12-03 2026-09-30 ok
qa-delivery-alt.cruciallearning.com 2 2026-07-08 2026-07-09 nodata
dev-delivery-alt.cruciallearning.com 2 2025-12-03 2026-05-28 ok
scormdemotest.cruciallearning.com 10 2026-05-07 2026-09-02 ok
trust.cruciallearning.com 13 2026-05-23 2026-09-19 ok
dev.cruciallearning.com 5 2026-05-10 2026-09-11 ok
udl-dev.cruciallearning.com 2 2026-07-02 2026-07-02 nodata
www.cruciallearning.com 5 2026-05-02 2026-09-03 ok
udl-sandbox.cruciallearning.com 2 2026-07-02 2026-07-02 nodata
clp-vpn-sandbox.cruciallearning.com 2 2026-06-16 2026-06-16 ok
delivery.cruciallearning.com 3 2025-06-15 2026-08-18 ok
qa-delivery.cruciallearning.com 3 2026-04-26 2026-09-26 ok
dev-delivery.cruciallearning.com 3 2025-06-15 2026-08-18 ok
faculty.cruciallearning.com 3 2025-09-17 2026-08-28 ok

Programmatic access, with DNS A records: API GET /v1/hosts/cruciallearning.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/cruciallearning.com.