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.

12 hosts · 351 ms

HostCertsFirst seenLast seenDNS
synoshi.com 29 2026-04-10 2026-10-05 ok
*.synoshi.com 15 2026-04-10 2026-10-05 —
click.send.synoshi.com 6 2026-06-30 2026-08-28 ok
bounces.send.synoshi.com 6 2026-06-30 2026-08-28 ok
images.send.synoshi.com 10 2026-05-12 2026-09-07 ok
click.info.synoshi.com 6 2026-06-30 2026-08-28 ok
bounces.info.synoshi.com 6 2026-06-30 2026-08-28 ok
tracktor.synoshi.com 10 2026-05-12 2026-09-08 ok
itlinks.synoshi.com 6 2026-05-12 2026-09-07 ok
mta-sts.synoshi.com 6 2026-06-19 2026-08-17 ok
support.synoshi.com 7 2026-05-19 2026-09-14 ok
www.synoshi.com 10 2026-05-12 2026-09-07 ok

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