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.

9 hosts · 297 ms

HostCertsFirst seenLast seenDNS
bigmailer.io 13 2026-01-06 2026-08-21 ok
*.bigmailer.io 1 2026-01-06 2026-01-06 —
lp0.bigmailer.io 1 2025-12-19 2025-12-19 ok
e.bigmailer.io 2 2026-02-24 2026-07-12 ok
lp.bigmailer.io 1 2025-12-19 2025-12-19 ok
docs.bigmailer.io 6 2026-05-07 2026-09-02 ok
affiliates.bigmailer.io 5 2026-05-15 2026-09-12 ok
grow.bigmailer.io 1 2026-01-26 2026-01-26 ok
www.bigmailer.io 12 2026-04-25 2026-08-21 ok

Programmatic access, with DNS A records: API GET /v1/hosts/bigmailer.io (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/bigmailer.io.