Find every subdomain
of a domain.

Every hostname under a domain that ever appeared in a public TLS certificate — with certificate counts and first/last seen dates.

8 hosts · 286 ms

HostCertsFirst seenLast seen
assentportal.com 1 2026-01-26 2026-01-26
smtp-in-01.assentportal.com 5 2026-04-23 2026-08-22
smtp-in-01.preprod.assentportal.com 3 2026-06-11 2026-08-10
mta01.preprod.assentportal.com 2 2025-09-30 2026-10-01
go.stg.assentportal.com 2 2026-03-11 2026-07-27
go.assentportal.com 3 2026-04-29 2026-09-29
go.cat.assentportal.com 1 2025-12-05 2025-12-05
eu.assentportal.com 1 2026-01-26 2026-01-26

Programmatic access: API GET /v1/hosts/assentportal.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/assentportal.com.