I'd like to know how I can handle discounts through the API and what scenario each use would be appropriate for.
The primary function of the Discount and Discounted Properties in the Avalara AvaTax API is to decrease the taxable/non-taxable Line Amount field(s) by a value specified in the GetTaxRequest.Discount property.
The Discount amount passed at the Document level must be in a decimal format representing a dollar amount. Percentages are ignored.
The Discount amount is then applied proportionally across line items within the document that have the Discounted property set to true. If no line items are selected to be “discounted” then the amount passed in the “Discount” field is ignored.
If you need to reflect manufacturer’s coupons or hostess credits, those should be reflected as a separate (negative) line item on your document with the appropriate tax code for the coupon type. These two cases are handled differently by different states.