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.

6 hosts · 354 ms

HostCertsFirst seenLast seen
whatsapp.com 535 2026-04-15 2026-10-12
*.whatsapp.com 535 2026-04-15 2026-10-12
email.user-research.whatsapp.com 3 2026-06-18 2026-08-17
autodiscover.whatsapp.com 1 2025-10-15 2025-10-15
wt.whatsapp.com 338 2026-04-15 2026-10-12
*.wt.whatsapp.com 338 2026-04-15 2026-10-12

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