Checkout Discounts

Adds a discount to an existing checkout.

Use this endpoint to apply the following discounts:

• Apply a manual discount to a cart. In this case, you can distribute the discount between each line item in the cart based on the item value.
• Apply a manual discount against a specific line item.
• Apply a manual discount at the item-level with a cart-level discount.

Notes:

• When you call this API, you clear out all existing discounts applied to line items, including product and order-based discounts.
• You cannot apply a manual discount to a specific line item if you have already applied a coupon or automatic promotion to it.

Required Fields:

• discounted_amount at the cart-level or at the item-level

To prevent lost updates due to concurrent requests overriding changes made by others, it is recommended to enable optimistic concurrency control by including the version field in the request payload. If the provided version does not match the version on the server, a conflict error will be returned, which the client can handle accordingly.