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.

9 hosts · 305 ms

HostCertsFirst seenLast seen
protonvpn.com 24 2026-05-07 2026-09-17
*.protonvpn.com 23 2026-05-18 2026-09-17
repo2.protonvpn.com 5 2026-05-05 2026-09-02
pvpndeb.protonvpn.com 5 2026-05-20 2026-09-17
join.protonvpn.com 5 2026-05-29 2026-09-16
*.join.protonvpn.com 5 2026-05-29 2026-09-16
repo.protonvpn.com 5 2026-05-05 2026-09-02
test-unified-repo.protonvpn.com 4 2026-06-08 2026-10-06
account.protonvpn.com 6 2026-05-07 2026-08-25

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