The Tax Calculation service plugin (formerly SPI) allows you to integrate a custom tax calculation service with Wix. Use the Tax Calculation service plugin together with the Tax Groups API and the Tax Regions API to customize your tax calculations.
The integration is done via an app created in the app dashboard with the Tax Calculation service plugin.
Learn more about implementing an service plugin with Wix.
country
and subdivision
with a specific tax treatment. Tax is calculated based on the tax region and the tax group associated with a line item. See the Tax Regions API.