Yes, it is possible to refund specific items in an order using the Square APIs. However, the Refunds API currently does not support itemized refunds. You can refund a specific line item in an order using the Square Point of Sale or other Square products, but not programmatically via the API.
For itemized refunds, the Orders API provides the return details in the ‘returns’ field of the Order object. This includes information such as the item type, catalog information of the refunded line item like catalog_object_id and variation_name.
For custom refunds, the ‘returns’ field has the item_type set to CUSTOM_AMOUNT and no other catalog item information.
When a refund is processed, Square also creates an Order object that provides the refund details. Both the itemized refund and custom refund create a return order (an Order object). The information in the ‘returns’ field varies for itemized and custom refunds.
However, if you need to refund a specific amount rather than a specific item, both the Square products and the Refunds API support custom refunds. In this case, a custom refund refers to refunding a specific order amount.
This answer was reviewed by @Bryan-Square.