These endpoints are called from your checkout UI before the subscriber completes their order. All three are public (no auth required).

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Check email availability

Check whether an email address is already registered as a kurnl account. The check is platform-wide — it is not scoped to your provider.

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Request body

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Response

Mind the polarity: is_taken: true means the email is already registered. Your checkout UI should then prompt the subscriber to log in instead of creating a new account.

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Check subscription at location

Check whether a location already has an active subscription. Used to block booking a second product at the same connection.

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Query parameters

Pass one of the two (there is no provider parameter):

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Response

has_active_subscription: true means the location already has an active subscription — your checkout UI should show an error or redirect.
This endpoint fails open: malformed input, an unknown location, or a backend error all return false. Treat false as “no conflict found”, not as a guaranteed negative — the provisioning endpoints enforce the authoritative checks.

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Validate discount code

Validate a discount code and return its terms so you can display them in the checkout UI.

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Request body

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Response — 200 OK (valid)

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Response — 200 OK (invalid)

error is free text (e.g. "Plan version not found", "Invalid or expired discount code").
The lookup matches on the code alone (non-archived): it is not scoped to the plan’s provider — another provider’s code can validate — and the data model has no expiry window, so “expired” never actually occurs. Treat a valid: true as advisory.
Discounts apply automatically at kurnl-billed checkout. No partner provisioning endpoint accepts a discount field — there is currently no way to attach a discount to a subscription via the partner API.

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Payments not configured (409)

The checkout-creation step that follows these helper calls — and the subscriber payment-method routes (see Subscriber Self-Service) — needs the provider’s own Stripe account. If that provider has not connected one, it returns 409:
Only the Kurnl marketplace checkout needs Stripe — a provider using the external checkout is unaffected. Check service_providers.tenant_configs.stripe_connected on the plan version (see Plans) before offering the Kurnl checkout in your UI.