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.

19 hosts · 345 ms

HostCertsFirst seenLast seenDNS
asktia.com 2 2025-06-13 2026-05-13 ok
*.asktia.com 4 2025-06-13 2026-05-13 —
selfhealth.asktia.com 1 2025-09-25 2025-09-25 ok
*.selfhealth.asktia.com 1 2025-09-25 2025-09-25 —
hi.asktia.com 19 2026-05-27 2026-09-22 ok
link.mail.asktia.com 2 2025-09-09 2026-08-09 ok
www.link.mail.asktia.com 2 2025-09-09 2026-08-09 nxdomain
join.asktia.com 16 2026-05-21 2026-09-16 ok
learn.asktia.com 3 2026-04-25 2026-08-23 ok
sso.asktia.com 3 2025-06-16 2026-07-13 ok
www.sso.asktia.com 3 2025-06-16 2026-07-13 nxdomain
help.asktia.com 2 2025-08-22 2026-07-23 nodata
get.help.asktia.com 2 2025-08-22 2026-07-23 ok
www.member.asktia.com 1 2026-05-05 2026-05-05 ok
sms.asktia.com 8 2026-08-01 2026-09-29 ok
link.notifications.asktia.com 2 2025-09-09 2026-08-09 ok
www.link.notifications.asktia.com 2 2025-09-09 2026-08-09 nxdomain
stressquiz.asktia.com 1 2026-03-26 2026-03-26 ok
*.stressquiz.asktia.com 1 2026-03-26 2026-03-26 —

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