# description
GET /api/domains/register/check — whether a domain can be registered through MailKite, and at what price. Read-only; no charge.

# properties.configured.description
False when domain registration isn't available on this deployment — the other fields are then placeholders.

# properties.premium.description
True for registry-premium names, which can't be registered here.

# properties.reason.description
Why an unavailable domain can't be registered (e.g. 'Already on MailKite').

# properties.price.description
What you'd actually be charged (registrar cost grossed up with fees). Absent when unavailable.