Below, we are going to go over tax service integration works, and if you want to know more about how to implement a client to connect your tax calculation provider to VTEX’s APIs, this recipe and example might help you.

In synchronous integration, VTEX’s Checkout API triggers and sends a request to the external tax service API whenever there are changes to a customer’s cart, such as adding or removing items.

Timeout for the request is five seconds. There is no retry in case of timeout. If the external service that responds to the request times out constantly, the store will not be able to finish the order. If this integration is active, it applies to all stores in that account.

Synchronous tax integration can be activated or deactivated through a request to the Checkout Configuration API.

First, it is necessary to GET the current orderForm settings from this endpoint:

https://{accountName}.{environment}.com.br/api/checkout/pvt/configuration/orderForm

Then, Checkout settings can be updated via a POST call to the same endpoint. The full request body can be found in the Update orderForm configuration, as well as more details on that API. Here we will focus on the taxConfiguration object, which defines the External Tax Service settings:

The most important data in this object is the url. This is the endpoint URL that the Checkout will query to receive the calculated taxes. In other words, this is the external API endpoint of the tax tool.

The authorizationHeader defines the value that the Checkout will use in the Authorization header of calls to the external tax calculation API. This field can be used to define the access credentials for this API.

Once the POST for the Checkout Configuration API has finished processing the request with this data, its synchronous integration with the Tax API is activated.

When a purchase is made in a store, the location from which the order is shipped matters for tax calculation purposes. Because of this, when items from White Label Sellers are part of an order, tax configuration for the marketplace (seller 1) is not taken into account for those items. Each seller must have its own tax service configuration in order for this type of integration function properly.

The tax calculation tool must provide an endpoint that will receive a POST request. In this request, Checkout provides a body in a specific format. This means that either the endpoint must be prepared to receive this body format, or the integration must contain a parser to adapt it to the correct format.

Let’s see an example of that body sent by Checkout:

This body has eight main fields:

Field	Type	Description
orderFormId	string	Order form ID.
salesChannel	string	Type of sales channel.
items	array	List of objects which are the order products, where dockId is a field that refers to its identification on the logistics system that contains information of its address.
totals	array	Total amount of the order form, divided into taxes, shipping, discounts, and the items themselves.
clientEmail	string	Client's email address.
shippingDestination	object	Shipping information. Mandatory field.
clientData	object	Information regarding the client that placed the order.
paymentData	object	Contains an array of payments, where there is information regarding the payment methods, etc.

In response to the request sent by Checkout, we expect an array of products, each with its own array of taxes. See the example below:

Field	Type	Description
id	string	Request item index, which means the SKU's position on the items array sent by the request body.
taxes	array	List of all the taxes types for an SKU.
name	string	Tax name that will appear on the checkout.
description	string	Informative field, which does not appear on the storefront.
value	number	Absolute numeric value that will be added to the original price.

In the example above, the only item in the items array has a cost of 10, and, including the calculated taxes returned by the tax calculation tool, the total value would be 10 + 3.48 + 22 = 35.48.

If no taxes apply to the items in the order, the expected response is an empty array ([]).

For the Checkout API to understand the request body, the content-type must be set to application/vnd.vtex.checkout.minicart.v1+json.

Jurisdiction fields

If you use Avalara as your tax calculation provider, response bodies might also include the following fields, which refer to the different jurisdictions that may apply according to location.

Field	Type	Description
jurisType	string	Type of jurisdiction that applies to calculation.
jurisCode	string	Unique code that identifies the appropriate jurisdiction.
jurisName	string	Name of the jurisdiction that applies to the calculation.

These fields are also read by Checkout and added to the priceTag.

Below is an example for values that may be contained in these fields, and you can download all of the jurisdictions and respective codes used by Avalara here.