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.

19 hosts · 354 ms

HostCertsFirst seenLast seenDNS
tanbooks.com 17 2025-10-07 2026-09-30 ok
*.tanbooks.com 4 2025-07-16 2026-08-10 —
media.tanbooks.com 1 2026-02-09 2026-02-09 nxdomain
www.media.tanbooks.com 1 2026-02-09 2026-02-09 nxdomain
e.tanbooks.com 5 2026-04-23 2026-10-01 ok
h.tanbooks.com 5 2026-05-04 2026-09-02 ok
acumen.tanbooks.com 2 2025-06-18 2026-06-18 ok
www.acumen.tanbooks.com 2 2025-06-18 2026-06-18 nxdomain
tandirection.tanbooks.com 4 2025-08-06 2026-08-06 nxdomain
www.tandirection.tanbooks.com 4 2025-08-06 2026-08-06 nxdomain
subscription.tanbooks.com 6 2026-05-18 2026-09-13 ok
go.tanbooks.com 5 2026-05-19 2026-10-04 ok
app.tanbooks.com 5 2026-05-07 2026-08-26 ok
click.updates.tanbooks.com 2 2026-10-05 2026-10-05 ok
links.tanbooks.com 2 2026-04-05 2026-09-05 ok
authors.tanbooks.com 6 2026-05-08 2026-08-14 ok
www.authors.tanbooks.com 3 2026-05-08 2026-08-14 nxdomain
t.tanbooks.com 2 2026-10-05 2026-10-05 ok
www.tanbooks.com 12 2025-10-07 2026-09-30 ok

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