# Integration and Testing
source: https://developer.mastercard.com/pay-with-rewards/tutorial/api-testing/index.md

This tutorial walks through the steps required to test the Pay with Rewards Service by building an end-to-end application.

## Introduction {#introduction}

This tutorial helps you to create a simple Java application that makes an API call to the Pay with Rewards Service in the Sandbox environment.

### What you will learn {#what-you-will-learn}

* How to set up the environment to develop a simple Java application
* How to generate an API client using the [OpenAPI Generator](https://openapi-generator.tech/)
* How to make an API call

### Prerequisites {#prerequisites}

To complete this tutorial, you will need:

* [JDK 11](https://www.java.com/en/) or later
* An IDE of your choice
* Mastercard Developers account with access to the Pay with Rewards API
* Pay with Rewards Open API specification (Refer to the [Open Specification](https://developer.mastercard.com/pay-with-rewards/documentation/api-reference/index.md) for details.)