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 · 374 ms

HostCertsFirst seenLast seenDNS
falk.us 82 2026-04-10 2026-10-05 ok
*.falk.us 26 2026-04-10 2026-10-04 —
time1.falk.us 1 2026-08-17 2026-08-17 ok
ha8.falk.us 5 2026-05-04 2026-09-11 ok
a.falk.us 13 2026-06-02 2026-09-28 ok
ha.falk.us 5 2026-05-01 2026-09-08 ok
scorecard.falk.us 15 2026-06-04 2026-09-30 ok
*.scorecard.falk.us 15 2026-06-04 2026-09-30 —
time.falk.us 1 2026-08-06 2026-08-06 ok
altovablog.falk.us 12 2026-06-05 2026-10-01 ok
alexander.falk.us 9 2026-06-03 2026-09-29 ok
optimize-images.falk.us 14 2026-04-11 2026-10-05 ok
workers.falk.us 16 2026-04-23 2026-08-19 nxdomain
mta-sts.falk.us 9 2026-06-02 2026-09-28 ok
clawdbot.falk.us 5 2026-05-25 2026-09-22 ok
www.falk.us 11 2026-06-02 2026-09-28 ok

Programmatic access, with DNS A records: API GET /v1/hosts/falk.us (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/falk.us.