Single step redemption for the checkout checkbox flow, i.e. a "Use my coins" checkbox on the cart or checkout. The discount is always the maximum the customer can get for the cart, there is no step selection.

• The offer used is the published or active offer with classification action_checkoutcheckbox. If the customer has a membership (or else a tier) and an offer restricted to that membership (or tier) exists, that offer is used instead of the universal one
• The discount is capped by the offer fiat_range, the customer's coin balance, the cart amount and the minimum cart configured on the offer
• Requires the Checkout Checkbox action to be active on the dashboard, otherwise the API fails
• Calls for the same customer are serialised, so concurrent calls from multiple tabs are safe

Actions

• list: returns points_balance and a promotions entry describing the discount that can be applied (coin_value to deduct, fiat_value discount, delta_amount payable after discount). If a valid coupon was already generated for this cart amount, it returns that coupon in coupons instead
• perform: generates the discount coupon and returns it in coupons. Use coupons[0].value as the discount code on the checkout (it starts with neccbox). The coins are deducted when the order is placed with the code, not at generation. The coupon expires in 24 hours if unused. Calling perform again with the same amount returns the existing coupon, calling it with a different amount cancels the old coupon and generates a new one
• revert: cancels the coupon generated earlier (status becomes unavailable and the discount code is removed from the store). Call this when the customer unticks the checkbox or removes the code

Errors are returned with a message such as "No discount is available" when the cart is below the minimum cart, the customer has no coins, or the offer is not configured.