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.

16 hosts · 267 ms

HostCertsFirst seenLast seenDNS
facebookmail.com 285 2026-04-10 2026-10-07 ok
*.facebookmail.com 285 2026-04-10 2026-10-07 —
cloud.mc.facebookmail.com 1 2025-10-21 2025-10-21 servfail
image.mc.facebookmail.com 2 2025-12-22 2025-12-22 ok
click.mc.facebookmail.com 1 2025-10-21 2025-10-21 ok
mediapartnerships.mc.facebookmail.com 1 2025-10-21 2025-10-21 ok
view.mc.facebookmail.com 1 2025-10-21 2025-10-21 ok
cloud.workplace-research.facebookmail.com 1 2026-09-29 2026-09-29 ok
cloud.facebook-research.facebookmail.com 1 2025-11-05 2025-11-05 ok
image.facebook-research.facebookmail.com 1 2026-01-03 2026-01-03 ok
click.facebook-research.facebookmail.com 1 2025-11-05 2025-11-05 ok
view.facebook-research.facebookmail.com 1 2025-11-05 2025-11-05 ok
cloud.frl-research.facebookmail.com 1 2025-11-05 2025-11-05 ok
image.frl-research.facebookmail.com 1 2026-01-03 2026-01-03 ok
msgin-regional.facebookmail.com 2 2025-07-28 2026-06-25 nxdomain
msgin.facebookmail.com 2 2025-07-28 2026-06-25 nxdomain

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