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.

44 hosts · 454 ms

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HostCertsFirst seenLast seen
blue10.com 5 2026-05-06 2026-09-19
wds1.blue10.com 3 2026-02-26 2026-10-10
eu1.blue10.com 2 2026-02-24 2026-07-14
wds2.blue10.com 3 2026-02-26 2026-10-10
eu2.blue10.com 2 2026-02-24 2026-07-14
wds3.blue10.com 3 2026-02-22 2026-10-07
eu3.blue10.com 2 2026-02-26 2026-07-15
alpha.blue10.com 2 2026-08-20 2026-08-20
odata.blue10.com 2 2026-03-02 2026-06-25
beta.blue10.com 2 2026-09-15 2026-09-15
web.blue10.com 2 2026-07-09 2026-09-09
authenticate.blue10.com 1 2026-06-11 2026-06-11
invite.blue10.com 1 2026-07-13 2026-07-13
api.blue10.com 4 2026-02-25 2026-10-09
caapi.blue10.com 3 2026-05-17 2026-09-30
werkenbij.blue10.com 5 2026-05-15 2026-09-11
www.werkenbij.blue10.com 4 2026-06-04 2026-10-02
internal.blue10.com 1 2026-05-17 2026-05-17
*.internal.blue10.com 1 2026-05-17 2026-05-17
cc.internal.blue10.com 3 2026-02-25 2026-10-10
fo.internal.blue10.com 2 2026-03-02 2026-07-19
skybox.internal.blue10.com 1 2026-07-07 2026-07-07
security.internal.blue10.com 3 2026-02-26 2026-10-12
maturity.internal.blue10.com 2 2026-03-20 2026-07-21
login.blue10.com 3 2026-02-25 2026-10-09
iprestrictedlogin.blue10.com 3 2026-02-22 2026-10-06
go.blue10.com 5 2026-04-23 2026-09-08
help.blue10.com 3 2026-01-17 2026-06-11
finvoices.blue10.com 2 2026-03-05 2026-06-28
signals.blue10.com 2 2026-03-05 2026-06-28
finops.blue10.com 3 2026-02-24 2026-10-09
contracts.blue10.com 2 2026-02-28 2026-07-18
beta.contracts.blue10.com 3 2026-02-28 2026-07-24
backoffice.contracts.blue10.com 2 2026-02-09 2026-07-04
api.contracts.blue10.com 2 2026-03-11 2026-06-25
documents.blue10.com 4 2026-02-22 2026-10-07
mta-sts.blue10.com 3 2026-05-12 2026-08-03
status.blue10.com 5 2026-06-08 2026-10-04
eu1-ws.blue10.com 3 2026-05-14 2026-09-26
eu2-ws.blue10.com 3 2026-05-17 2026-09-30
eu3-ws.blue10.com 3 2026-05-15 2026-09-28
content.blue10.com 2 2026-01-18 2026-06-11
support.blue10.com 6 2026-05-06 2026-09-19
www.blue10.com 5 2026-05-05 2026-09-18

Programmatic access: API GET /v1/hosts/blue10.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/blue10.com.