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.

10 hosts · 313 ms

HostCertsFirst seenLast seenDNS
trello.com 84 2025-06-30 2026-10-03 ok
*.trello.com 84 2025-06-30 2026-10-03 —
c.trello.com 1 2025-08-30 2025-08-30 nodata
blog.trello.com 12 2026-04-22 2026-08-18 ok
br.blog.trello.com 4 2026-05-19 2026-05-19 nodata
sptrack.trello.com 2 2026-04-11 2026-09-11 ok
files-dl.trello.com 1 2025-12-17 2025-12-17 ok
info.trello.com 8 2026-05-19 2026-05-19 nodata
files.trello.com 1 2025-12-05 2025-12-05 ok
developers.trello.com 125 2025-06-16 2026-09-09 ok

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