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.

31 hosts · 277 ms

HostCertsFirst seenLast seenDNS
healthoptimisation.com 16 2026-04-24 2026-08-22 ok
2022.healthoptimisation.com 5 2026-05-27 2026-09-24 ok
2023.healthoptimisation.com 4 2026-04-12 2026-08-10 ok
2024.healthoptimisation.com 4 2026-06-08 2026-10-06 ok
2025.healthoptimisation.com 5 2026-05-20 2026-09-17 ok
2026.healthoptimisation.com 3 2025-09-13 2026-07-25 ok
2019.healthoptimisation.com 3 2026-04-22 2026-05-21 ok
usa.healthoptimisation.com 21 2026-05-23 2026-09-20 ok
send.healthoptimisation.com 5 2026-05-27 2026-09-24 ok
course.healthoptimisation.com 13 2026-05-28 2026-09-24 ok
live.healthoptimisation.com 6 2026-05-13 2026-09-08 ok
book.healthoptimisation.com 5 2026-05-12 2026-09-09 ok
uk.healthoptimisation.com 17 2025-09-14 2026-09-26 ok
austin.healthoptimisation.com 7 2026-05-08 2026-09-03 ok
shop.healthoptimisation.com 4 2026-03-16 2026-08-11 ok
2019teaser.healthoptimisation.com 5 2026-05-25 2026-09-22 ok
2019recordings.healthoptimisation.com 5 2026-05-25 2026-09-22 ok
2022videos.healthoptimisation.com 4 2026-04-19 2026-08-18 ok
2023videos.healthoptimisation.com 4 2026-04-20 2026-08-18 ok
2024videos.healthoptimisation.com 4 2026-04-16 2026-08-14 ok
usa2025videos.healthoptimisation.com 5 2026-05-03 2026-09-01 ok
uk2025videos.healthoptimisation.com 4 2026-06-06 2026-10-04 ok
2019videos.healthoptimisation.com 5 2026-05-25 2026-09-22 ok
ss.healthoptimisation.com 5 2026-06-04 2026-10-02 ok
retreat.healthoptimisation.com 9 2026-05-25 2026-09-21 ok
summit.healthoptimisation.com 2 2025-08-13 2026-06-24 ok
content.healthoptimisation.com 5 2026-04-29 2026-10-06 ok
podcast.healthoptimisation.com 1 2026-01-02 2026-01-02 ok
www.healthoptimisation.com 9 2026-04-24 2026-08-21 ok
community.healthoptimisation.com 8 2026-06-23 2026-08-21 ok
party.healthoptimisation.com 2 2026-05-02 2026-05-02 nxdomain

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