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.

22 hosts · 197 ms

HostCertsFirst seenLast seen
opti.se 2 2026-03-17 2026-08-17
*.opti.se 5 2026-04-27 2026-08-25
infra.opti.se 6 2026-06-03 2026-10-01
*.infra.opti.se 6 2026-06-03 2026-10-01
meta.opti.se 5 2026-06-06 2026-10-05
prod.opti.se 5 2026-04-28 2026-08-26
*.prod.opti.se 5 2026-04-28 2026-08-26
ci-webhook.prod.opti.se 5 2026-04-28 2026-08-26
app.prod.opti.se 5 2026-05-25 2026-09-23
are.opti.se 5 2026-05-22 2026-09-09
www.are.opti.se 5 2026-05-23 2026-09-05
blog.opti.se 6 2026-06-18 2026-09-26
email.opti.se 5 2026-05-30 2026-09-27
vpn.opti.se 5 2026-05-04 2026-09-01
app.opti.se 5 2026-05-16 2026-09-15
docker.opti.se 6 2026-06-03 2026-10-01
dev.opti.se 5 2026-06-10 2026-10-08
app-dev.opti.se 5 2026-05-16 2026-09-15
*.dev.opti.se 5 2026-06-10 2026-10-08
meta.dev.opti.se 5 2026-06-07 2026-10-06
app.dev.opti.se 5 2026-05-25 2026-09-23
www.opti.se 5 2026-05-20 2026-09-18

Programmatic access: API GET /v1/hosts/opti.se (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/opti.se.