# Postman Collection
source: https://developer.mastercard.com/enhanced-currency-conversion-calculator/documentation/developer-tools/postman-collection/index.md

Postman is an application for easy RESTful API exploration. You can use Postman to test API calls multiple times without having to write code, and save multiple sets of credentials to quickly test the Enhanced Currency Conversion Calculator API in Sandbox and Production.

## Fork the Collection {#fork-the-collection}

Use the button below to fork Mastercard's Postman collection and explore the API.
Click: [![](https://static.developer.mastercard.com/content/enhanced-currency-conversion-calculator/uploads/postman-button.svg)](https://www.postman.com/mastercard/workspace/mastercard-developers/collection/26779181-d03f82fd-5ad4-4ec6-841b-fde69aebbd81)

## Set Up Environment Variables {#set-up-environment-variables}

Create (or edit) a Postman environment with a variable for the base URL, and switch it between Sandbox and Production as needed:

| Variable  |                                  Sandbox value                                   |                             Production value                             |
|-----------|----------------------------------------------------------------------------------|--------------------------------------------------------------------------|
| `baseUrl` | `https://sandbox.api.mastercard.com/enhanced/settlement/currencyrate/subscribed` | `https://api.mastercard.com/enhanced/settlement/currencyrate/subscribed` |

## Configure OAuth 1.0a Authentication {#configure-oauth-10a-authentication}

The Enhanced Currency Conversion Calculator API requires every request to carry an OAuth 1.0a `Authorization` header. On the collection or request's **Authorization** tab, select **OAuth 1.0a**, then supply:

* **Consumer Key** --- from your Mastercard Developers project.
* **Signing Key** --- generated from your project's `.p12` file (Postman's Mastercard OAuth 1.0a support expects the private key in PEM format; export it from your `.p12` first).
* **Signature Method** --- `RSA-SHA256`.

See the [Postman tutorial](https://developer.mastercard.com/platform/tutorial/use-postman-for-mastercard-apis/) for the generic, detailed steps to get Mastercard authentication working in Postman.

## Run a Request {#run-a-request}

Select the `GET summary-rates` request in the forked collection, confirm `{{baseUrl}}` resolves to Sandbox, and send it with the sample query parameters already populated (`rate_date`, `trans_curr`, `trans_amt`, `crdhld_bill_curr`) to confirm your credentials are configured correctly before moving on to the other endpoints.

## Next Steps {#next-steps}

|                                                            Category                                                            |                     Description                      |
|--------------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------|
| [Testing](https://developer.mastercard.com/enhanced-currency-conversion-calculator/documentation/testing/index.md)             | Positive and negative test cases for every endpoint. |
| [API Reference](https://developer.mastercard.com/enhanced-currency-conversion-calculator/documentation/api-reference/index.md) | Try the Sandbox APIs directly from your browser.     |