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.

16 hosts · 248 ms

HostCertsFirst seenLast seen
helpdesk.com 34 2025-07-22 2026-10-08
*.helpdesk.com 28 2025-07-22 2026-10-08
staging.helpdesk.com 11 2025-07-22 2026-08-18
*.staging.helpdesk.com 15 2025-07-22 2026-10-08
*.app.staging.helpdesk.com 8 2026-03-11 2026-10-08
labs.helpdesk.com 12 2025-07-22 2026-08-14
*.labs.helpdesk.com 16 2025-07-22 2026-10-08
portal.labs.helpdesk.com 5 2026-05-26 2026-09-23
*.app.labs.helpdesk.com 8 2026-03-11 2026-10-08
customer-insight.labs.helpdesk.com 5 2026-04-26 2026-08-24
hs.helpdesk.com 10 2026-04-28 2026-08-24
status.helpdesk.com 5 2026-04-30 2026-09-03
news.helpdesk.com 10 2026-04-25 2026-08-23
customer-insight.helpdesk.com 5 2026-04-26 2026-08-24
support.helpdesk.com 7 2025-11-09 2026-10-09
www.helpdesk.com 6 2026-04-28 2026-08-26

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