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 · 331 ms

HostCertsFirst seenLast seenDNS
sequel.co 38 2026-04-11 2026-10-05 ok
*.sequel.co 7 2026-05-14 2026-09-19 —
sigma.sequel.co 5 2026-05-18 2026-09-20 ok
email-sigma.sequel.co 3 2026-05-28 2026-09-10 ok
brand.sequel.co 5 2026-04-22 2026-08-15 ok
fund.sequel.co 3 2026-10-01 2026-10-01 ok
sable.sequel.co 6 2026-05-16 2026-09-16 ok
book.sequel.co 1 2026-10-07 2026-10-07 ok
founderportal.sequel.co 13 2026-05-28 2026-09-23 ok
email.sequel.co 3 2026-05-28 2026-09-12 ok
email.tm.sequel.co 3 2026-06-17 2026-10-02 ok
email.sn.sequel.co 3 2026-06-17 2026-10-03 ok
jobs.sequel.co 7 2026-04-26 2026-09-22 ok
uploads.sequel.co 3 2026-06-07 2026-08-07 ok
founderfiles.sequel.co 5 2026-05-07 2026-09-09 ok
email.news.sequel.co 2 2026-06-17 2026-08-13 ok
tst.sequel.co 26 2026-04-11 2026-10-05 ok
www.sequel.co 5 2026-05-06 2026-09-09 ok
email.sigma-notify.sequel.co 3 2026-05-28 2026-09-13 ok

Programmatic access, with DNS A records: API GET /v1/hosts/sequel.co (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/sequel.co.