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.

60 hosts · 213 ms

HostCertsFirst seenLast seen
halcyon.ai 78 2025-07-09 2026-10-08
*.halcyon.ai 65 2025-07-09 2026-10-08
sirena.halcyon.ai 1 2026-07-23 2026-07-23
ae.halcyon.ai 14 2025-08-11 2026-09-14
*.ae.halcyon.ai 23 2025-08-11 2026-10-08
console.ae.halcyon.ai 10 2026-05-03 2026-08-29
portal.ae.halcyon.ai 1 2025-08-11 2025-08-11
*.portal.ae.halcyon.ai 9 2025-08-11 2026-10-08
terminus.portal.ae.halcyon.ai 4 2026-05-04 2026-07-02
console.halcyon.ai 8 2026-05-08 2026-09-03
povkickoff.halcyon.ai 5 2026-05-16 2026-09-14
jghwh.halcyon.ai 5 2026-05-16 2026-09-14
pmbounces.feedback.halcyon.ai 8 2026-05-13 2026-09-08
click.halcyon.ai 15 2026-06-03 2026-09-29
global.halcyon.ai 1 2026-02-16 2026-02-16
*.global.halcyon.ai 1 2026-02-16 2026-02-16
sirena-api.internal.halcyon.ai 1 2026-08-07 2026-08-07
portal.halcyon.ai 1 2025-11-16 2025-11-16
*.portal.halcyon.ai 11 2025-11-16 2026-08-11
terminus.portal.halcyon.ai 6 2026-05-03 2026-07-01
supportal.halcyon.ai 6 2026-01-22 2026-09-21
otel.halcyon.ai 1 2026-05-18 2026-05-18
email.gh-mail.halcyon.ai 8 2026-05-13 2026-09-08
sl.halcyon.ai 4 2026-04-14 2026-08-12
beacon.halcyon.ai 2 2025-08-15 2026-07-16
aefo.halcyon.ai 4 2026-03-02 2026-03-04
*.aefo.halcyon.ai 16 2026-03-02 2026-09-14
*.portal.aefo.halcyon.ai 6 2026-05-02 2026-08-28
info.halcyon.ai 13 2026-04-18 2026-08-15
go.halcyon.ai 15 2026-05-03 2026-09-07
ap.halcyon.ai 5 2025-08-13 2026-07-14
*.ap.halcyon.ai 17 2025-08-13 2026-08-11
console.ap.halcyon.ai 10 2026-05-07 2026-09-03
portal.ap.halcyon.ai 1 2025-08-13 2025-08-13
*.portal.ap.halcyon.ai 13 2025-08-13 2026-08-11
terminus.portal.ap.halcyon.ai 4 2026-05-03 2026-07-01
halcyonvr.halcyon.ai 2 2026-04-24 2026-04-24
docs.halcyon.ai 10 2026-05-01 2026-08-28
services.halcyon.ai 1 2026-04-22 2026-04-22
hades.halcyon.ai 1 2026-09-18 2026-09-18
ransomwareattacks.halcyon.ai 8 2026-05-04 2026-08-31
thanks.halcyon.ai 2 2025-08-18 2026-07-19
forms.halcyon.ai 4 2026-09-01 2026-09-01
partners.halcyon.ai 2 2025-09-01 2026-08-02
mta-sts.halcyon.ai 5 2026-05-30 2026-09-27
status.halcyon.ai 5 2026-05-09 2026-09-05
data.product.halcyon.ai 3 2026-06-15 2026-08-17
content.product.halcyon.ai 3 2026-06-15 2026-08-16
support.halcyon.ai 2 2025-08-18 2026-07-19
global-test.halcyon.ai 1 2025-07-10 2025-07-10
*.global-test.halcyon.ai 1 2025-07-10 2025-07-10
trust.halcyon.ai 13 2026-04-23 2026-09-28
eu.halcyon.ai 5 2025-08-20 2026-07-21
*.eu.halcyon.ai 13 2025-08-20 2026-10-08
console.eu.halcyon.ai 8 2026-05-08 2026-09-03
portal.eu.halcyon.ai 1 2025-08-20 2025-08-20
*.portal.eu.halcyon.ai 9 2025-08-20 2026-10-08
terminus.portal.eu.halcyon.ai 4 2026-05-03 2026-07-01
www.halcyon.ai 12 2026-05-04 2026-08-30
bounty.halcyon.ai 4 2026-06-09 2026-10-08

Programmatic access: API GET /v1/hosts/halcyon.ai (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/halcyon.ai.