# Integration and Testing
source: https://developer.mastercard.com/priceless-planet-carbon-tracker/documentation/integration-and-testing/index.md

## Ready to begin Testing? {#ready-to-begin-testing}

Tip: We recommend that you begin testing in the sandbox.

Once you have created a project on Mastercard Developers, generated sandbox credentials and received approvals, you can start testing.

Start by following our:

## 1. Mastercard Carbon Calculator Experience API test cases tutorial {#1-mastercard-carbon-calculator-experience-api-test-cases-tutorial}

Follow our [Carbon Calculator Experience API Testing Tutorial](https://developer.mastercard.com/priceless-planet-carbon-tracker/tutorial/test-cases/index.md) for help about Carbon Calculator Experience API test cases.

## 2. Base URLs for testing {#2-base-urls-for-testing}

* Sandbox
* Production

```sandbox
https://sandbox.api.mastercard.com/cts

```

```production
https://api.mastercard.com/cts

```

## Methods to test Sandbox {#methods-to-test-sandbox}

### 1. Reference application {#1-reference-application}

> * Our Java Reference Applications acts as an API client and allows you to integrate different operations.
> * For detailed steps, follow our [Reference Application Page](https://developer.mastercard.com/priceless-planet-carbon-tracker/documentation/reference-app/index.md).

### 2. Postman {#2-postman}

> * [Postman Collections](https://www.postman.com/product/collections/) is an API client that allows developers to test your API's calls in sandbox and production environments without writing any code. This makes sharing pre-formed API requests with partners extremely easy, and permits partners to run individual API requests or those within a folder or the entire collection.
> * For detailed steps, follow our [Postman Collections Page](https://developer.mastercard.com/priceless-planet-carbon-tracker/documentation/postman-collection/index.md).

### 3. Insomnia {#3-insomnia}

> * [Insomnia](https://insomnia.rest/) is an open-source API client that developers use to quickly and easily send REST requests to Mastercard APIs. API Consultancy \& Standards developed an [Insomnia Plugin](https://github.com/Mastercard/insomnia-plugin-mastercard) for handling API authentication.
> * Follow our [Insomnia Tutorial](https://developer.mastercard.com/priceless-planet-carbon-tracker/tutorial/how-to-install-and-configure-insomnia-tool/index.md) to learn how to test the Carbon Calculator Experience API using Insomnia.

👉Download our Insomnia Collection here:
[Insomnia_collection_2025.json](https://static.developer.mastercard.com/content/priceless-planet-carbon-tracker/uploads/Insomnia_collection_2025.json) (43KB)

## Next Steps {#next-steps}

* Now that you have an understanding of testing, you can proceed to the [Postman Collections](https://developer.mastercard.com/priceless-planet-carbon-tracker/documentation/postman-collection/index.md) section to fork our Postman Collections and begin making calls.
* You can head to our [Reference Application](https://developer.mastercard.com/priceless-planet-carbon-tracker/documentation/reference-app/index.md) page to download our Java Application that shows a typical usage of the Carbon Calculator Experience API.
* To learn more about any error codes you receive, head over to our [Codes and Formats](https://developer.mastercard.com/priceless-planet-carbon-tracker/documentation/code-and-formats/index.md) section to learn about the details of all the error codes.