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 · 328 ms

HostCertsFirst seenLast seenDNS
cside.com 136 2026-04-25 2026-09-19 ok
*.cside.com 23 2026-04-25 2026-08-22 —
og.cside.com 8 2026-05-21 2026-09-16 ok
prehog.cside.com 1 2026-05-12 2026-05-12 ok
dash.cside.com 10 2026-05-14 2026-09-09 ok
documentation.cside.com 10 2026-05-20 2026-09-15 ok
demo.cside.com 8 2026-04-29 2026-08-25 ok
*.demo.cside.com 8 2026-04-29 2026-08-25 —
mcp.cside.com 8 2026-04-27 2026-08-23 ok
*.mcp.cside.com 8 2026-04-27 2026-08-23 —
docs.cside.com 6 2026-05-20 2026-09-15 ok
status.cside.com 4 2026-06-03 2026-10-06 ok
trust.cside.com 4 2026-04-17 2026-09-17 ok
dash-canary.cside.com 2 2026-04-28 2026-04-28 ok
*.dash-canary.cside.com 2 2026-04-28 2026-04-28 —
directory.cside.com 24 2026-05-17 2026-09-13 ok

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