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.

15 hosts · 300 ms

HostCertsFirst seenLast seen
seguno.com 10 2026-04-15 2026-08-11
*.seguno.com 7 2025-07-22 2026-09-08
seguno1.seguno.com 13 2026-05-17 2026-09-28
swag.seguno.com 12 2026-05-19 2026-09-28
link.seguno.com 2 2025-09-29 2026-08-29
mjml.seguno.com 2 2026-03-16 2026-08-16
darkroom.seguno.com 1 2026-01-14 2026-01-14
cdn.seguno.com 1 2025-12-04 2025-12-04
demo.seguno.com 15 2026-05-16 2026-09-27
seguno-com-popups.seguno.com 18 2026-05-29 2026-10-03
support.seguno.com 2 2025-07-17 2025-12-11
www.seguno.com 12 2026-04-30 2026-08-27
mail-www.seguno.com 2 2025-07-23 2026-06-22
olfactory.seguno.com 2 2025-09-20 2026-08-21
proxy.seguno.com 2 2025-06-30 2026-05-31

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