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.

4 hosts · 316 ms

HostCertsFirst seenLast seenDNS
tendergrass.com 4 2026-04-19 2026-08-19 ok
*.tendergrass.com 4 2026-04-19 2026-08-19 —
fieldnotes.tendergrass.com 1 2026-09-21 2026-09-21 ok
develop.fieldnotes.tendergrass.com 1 2026-09-21 2026-09-21 ok

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