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.

44 hosts · 278 ms

HostCertsFirst seenLast seen
studycat.com 29 2026-01-15 2026-10-05
*.studycat.com 17 2026-01-15 2026-10-05
infra.api.qa.studycat.com 2 2026-02-24 2026-07-12
infoprod.studycat.com 10 2026-06-08 2026-10-04
redash.studycat.com 4 2026-04-20 2026-08-18
bizdash.studycat.com 3 2026-06-13 2026-08-13
auth.studycat.com 2 2025-06-21 2026-05-21
umami.studycat.com 4 2026-04-20 2026-08-18
infra.api.studycat.com 3 2026-05-04 2026-10-04
store.api.studycat.com 2 2025-09-22 2026-08-23
auth.api.studycat.com 3 2026-05-03 2026-10-03
slack.api.studycat.com 1 2025-11-19 2025-11-19
marcom.api.studycat.com 2 2025-12-14 2026-07-16
ops.api.studycat.com 1 2025-11-20 2025-11-20
users.api.studycat.com 5 2026-03-13 2026-10-04
connect.api.studycat.com 2 2025-09-22 2026-08-23
login.studycat.com 4 2026-04-12 2026-08-25
help.studycat.com 5 2026-05-06 2026-09-04
wapp.studycat.com 11 2026-06-01 2026-09-27
wp.studycat.com 10 2026-05-03 2026-08-29
schools.studycat.com 2 2025-09-13 2026-08-14
worksheets.studycat.com 12 2026-06-11 2026-10-08
auth.ws.studycat.com 2 2025-12-15 2025-12-15
wapp-dev.studycat.com 13 2026-06-08 2026-10-04
auth.dev.studycat.com 2 2026-04-15 2026-09-15
infra.api.dev.studycat.com 2 2025-09-24 2026-08-25
store.api.dev.studycat.com 2 2025-09-23 2026-08-24
auth.api.dev.studycat.com 2 2026-02-28 2026-07-16
slack.api.dev.studycat.com 2 2025-09-23 2026-08-24
playbook.api.dev.studycat.com 2 2026-07-06 2026-07-06
marcom.api.dev.studycat.com 4 2025-09-23 2026-08-24
ops.api.dev.studycat.com 4 2025-10-21 2026-09-21
users.api.dev.studycat.com 5 2026-03-12 2026-09-20
connect.api.dev.studycat.com 1 2025-12-14 2025-12-14
playbook.dev.studycat.com 1 2026-07-06 2026-07-06
login.dev.studycat.com 5 2026-04-13 2026-08-25
info.dev.studycat.com 2 2026-09-30 2026-10-01
subs.dev.studycat.com 5 2025-08-05 2025-08-05
auth.ws.dev.studycat.com 2 2025-10-02 2026-09-02
curiosity.dev.studycat.com 2 2026-08-13 2026-08-13
preview.studycat.com 12 2026-04-19 2026-08-15
infopreview.studycat.com 14 2026-06-08 2026-10-04
airflow.studycat.com 4 2026-04-20 2026-08-18
www.studycat.com 20 2026-04-30 2026-08-26

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