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 · 313 ms

HostCertsFirst seenLast seenDNS
bankopen.co 5 2025-09-12 2026-09-01 ok
*.bankopen.co 1 2025-09-12 2025-09-12 —
c494159490edcf6e13fc0e245723e0c8.bankopen.co 1 2026-04-24 2026-04-24 ok
www.c494159490edcf6e13fc0e245723e0c8.bankopen.co 1 2026-04-24 2026-04-24 nxdomain
open-itdashboard.bankopen.co 5 2026-04-20 2026-09-26 ok
icp-api.bankopen.co 2 2026-04-29 2026-04-29 ok
uat-icp-api.bankopen.co 2 2026-06-01 2026-06-01 ok
open-isms.bankopen.co 4 2026-05-29 2026-09-13 ok
www.bankopen.co 4 2025-12-09 2026-09-01 ok

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