# API Basics
source: https://developer.mastercard.com/payment-currency-conversion/documentation/api-basics/index.md

## API Security {#api-security}

### Client authentication {#client-authentication}

Mastercard uses OAuth 1.0a for authenticating your application. You can manage your authentication keys from your [Developer Dashboard](https://developer.mastercard.com/dashboard) after you created a project using the **Currency Conversion for Originating Institution** API service.
Tip: Do you want to learn more about the authentication scheme Mastercard uses? For that, read our [Using OAuth 1.0a to Access Mastercard APIs](https://developer.mastercard.com/platform/documentation/authentication/using-oauth-1a-to-access-mastercard-apis/) guide.

### Transport encryption {#transport-encryption}

The transport between client applications and Mastercard is secured using [TLS/SSL](https://en.wikipedia.org/wiki/Transport_Layer_Security), which means data are encrypted by default when transmitted across networks.

## How to Consume the Currency Conversion Calculator API? {#how-to-consume-the-currency-conversion-calculator-api}

There are multiple ways of integrating with the Currency Conversion Calculator service:

* Using a generated API client (recommended)
* Using a method of your choice

### Generating your own API client {#generating-your-own-api-client}

Create customizable API clients from the Currency Conversion Calculator API specification and let Mastercard open-source client libraries handle the authentication for you. This approach offers more flexibility and is strongly recommended.

For this, please follow our [Generating and Configuring a Mastercard API Client](https://developer.mastercard.com/platform/documentation/getting-started-with-mastercard-apis/generating-and-configuring-a-mastercard-api-client/) tutorial with the following API specification:
[currency-conversion-oi.yaml](https://static.developer.mastercard.com/content/payment-currency-conversion/swagger/currency-conversion-oi.yaml) (22KB)

### Using a method of your choice {#using-a-method-of-your-choice}

The Currency Conversion Calculator service exposes a REST API: you are free to use the REST/HTTP client of your choice and can still leverage the Mastercard open-source [client libraries](https://developer.mastercard.com/platform/documentation/authentication/using-oauth-1a-to-access-mastercard-apis/#client-libraries) for signing your requests.

For that, please refer to the Currency Conversion Calculator [REST API Reference](https://developer.mastercard.com/payment-currency-conversion/documentation/api-reference/index.md).

## Environments {#environments}

The table below describes the two different environments that are available.

| Environment |                                                                                                                                                                 Description                                                                                                                                                                  |
|-------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Sandbox     | Early-access environment containing mock APIs, enabling you to try the APIs quickly to assist with integration and solution development. The Sandbox returns mock values that should not be used for production transactions. Use your Sandbox keys to authenticate with this environment. The keys are set up when you create your project. |
| Production  | Full production environment containing the latest production API release. Use your Production keys to authenticate with this environment. The keys are set up when you request Production access for your project (via your project page).                                                                                                   |

Note: Due to its simplicity, this service does not have Mastercard Test Facility (MTF) APIs and test cases.