Additional costs

Hi Tiffany, A percentage based fee can be calculated using the options that are passed into the calculateAdditionalFees() function. The total price can be aggregated from all the line items and multiplied by the percentage. https://dev.wix.com/docs/velo/api-reference/wix-ecom-v2/service-plugins-spis/ecom-additional-fees/calculate-additional-fees For example:

import wixSiteBackend from "wix-site-backend";

const FEE = 0.3; //30% fee

export const calculateAdditionalFees = async (options) => {
  let additionalFees = [];

  const currency = await wixSiteBackend.generalInfo.getPaymentCurrency();

const {lineItems} = options;

const totalPrice = lineItems.reduce((total, item)=> Number(item.price)*item.quantity, 0);

additionalFees.push({
      code: "percentage-fee",
      name: "Percentage Fee",
      price: String(totalPrice*FEE),
      taxDetails: {
        taxable: true,
     },
});

  return {
    currency,
    additionalFees,
  };
};

Note - the above code is untested. Best, Eitan