To integrate the service with your applications, you use the APIs.

For example, you can use the Seller Transactions API to integrate the service with your applications and configure how it integrates with your solution. You use a combination of an API endpoint and method (called a request) to perform various functions. Transaction details are specified in JSON objects that are attached to these requests. The API returns information, in the same format, as responses.

Overview

The service includes the following REST APIs:

Seller Transaction API: Use this API to integrate the service with your store or applications. It provides liability and tax calculation as well as other services. You can use it to model your transactions. See Transaction Modeling.
Standalone Tax ID Validator API: Use this API if you want to use Vertex Validator on its own. See Standalone Vertex Validator.

This table lists those APIs, endpoints, and requests:

API	Endpoint	Requests
Seller Transaction API	Transaction (`/api/v3/seller/transactions`)	Store Transaction, Confirm Transaction, Refund Transaction, and Retrieve Transaction Requests
Seller Transaction API	Taxes (`/api/v3/seller/tax`)	Calculate Tax
Seller Transaction API	Refunds (`/api/v3/seller/transactions/{key}/refunds`)	Refund Transaction
Vertex Validator API	Tax Validations (`/api/v3/tax_numbers/`)	Validate Tax Number

API components

The API consists of two main components:

Requests: Used to integrate the service's features with your checkout process.
JSON Objects: Used to model transaction and other details. You use these to send information to the API and it is sent back by the API in the same format.

Requests

Requests are a combination of an HTTP method and an endpoint that you can use to integrate a function with your checkout process. You send requests to the API and it returns responses. Information is modeled in JSON objects that are attached to the requests and responses.

The following table summarizes the relationship between your checkout processes and the API request that you use to integrate it with the relevant feature:

Checkout Process	API Request	Vertex for eCommerce
Show tax on your store’s page.	Calculate Tax	Tax is calculated and information returned.
Calculate tax and store it until payment details are confirmed. For example, a good is in their basket but they have not yet paid for it.	Store Transaction	Transaction is stored as pending in Vertex.
Confirm a transaction when the payment details are confirmed. For example, your customer completes a purchase.	Confirm Transaction	Transaction is stored in Vertex. Details returned.
Integrate the service with your refund process.	Refund Transaction	Refund recorded in Vertex's database.
Retrieve a specific transaction, for example, for an information screen.	Retrieve Transaction	Transaction details returned by the API.
Retrieve the requests associated with a specific transaction.	Retrieve Transaction Requests	Requests for the specified transaction are returned.

JSON objects

You use JSON objects that you can attach to your requests to model information about transactions such as payment details, tax information, line information, addresses, and other details you may require for processing the transaction.

These are listed in the Fields Reference section.

In this section

Topic	Description
API Authentication	Read about how you can use tokens for API authentication.
Integrating with your Store and Applications	Read an overview of how you can use the API's request to integrate the service with your store or applications.
Transaction Processing	Read some examples of how different types of transactions are processed.
Transaction Keys	Read about how transaction keys are generated and used.