Create a purchase

Records a purchase against a subscriber, identified by email_address — use this to sync order data from your e-commerce platform into Kit so it appears on the subscriber's profile and can drive purchase-based automations. If no subscriber with that email address exists, one is created (in the active state) as part of the request.

Provide the external transaction_id (required), monetary breakdown (subtotal, tax, shipping, discount, total), a 3-letter currency code (e.g. USD), transaction_time, and the purchased products — each product needs a pid (your platform's product identifier); products that don't exist yet are created automatically.

Note: purchases are matched on transaction_id, so submitting one that already exists updates the existing purchase instead of creating a duplicate. The products in your request are added to that purchase as additional line items — they don't replace the ones already recorded — so resending the same products will duplicate the line items. Only include products you haven't already synced for that transaction_id.

Returns 422 when required parameters are missing or invalid.