# Support
source: https://developer.mastercard.com/currency-conversion-calculator/documentation/support/index.md

## FAQ {#faq}

Available to Mastercard issuers in NA (North America), LAC (Latin America), MEA (Middle East and Africa), Europe \[Excluding EEA\] and AP (Asia Pacific) regions. The APIs are RESTful APIs with OAuth security. Your API requests must have an OAuth 1.0a Authorization Header for authentication, see [**API Basics**](https://developer.mastercard.com/payment-currency-conversion/documentation/api-basics/).

The APIs do not use additional encryption. Your API GET requests do not have body payloads.
Yes, the Sandbox APIs are provided so that you can try the APIs quickly. They are API stubs that return simulated, static responses. The expandable sections in [**API Reference**](https://developer.mastercard.com/currency-conversion-calculator/documentation/api-reference/) provide **Execute** buttons that allow you to try the Sandbox APIs quickly, directly from your browser.

When you are ready to make API calls to the Sandbox server from an API tool or your application, you must create a Mastercard Developers project choosing the **Standard** **Currency Conversion Calculator** API service. See [**Getting Started**](https://developer.mastercard.com/currency-conversion-calculator/documentation/).
Note: Please note there is a per hour quota of 150 API calls in the sandbox environment. This quota does not affect production. We recommend that customers call the API each time there is a request from the cardholder using the Issuer user interface to retrieve the effective rate at the time.

For more information, please refer to the support article *What time does Mastercard publish its rates and what is the effective time period for the rates*
Mastercard Conversion rates are published once per day and the rates are effective for a 24-hour period. Please refer to the [**Currency Conversion Rates guide**](https://developer.mastercard.com/currency-conversion-calculator/documentation/tutorials-guides/#guides) Currently there is no throttling limit for this API. Please refer to **How many times should I call the API? Are there any best practices I should follow?** for more information. The average response time for our API is typically within a few seconds, ensuring fast and efficient access to currency conversion data. The API can handle up to 1,000 transactions per second (TPS). The currency conversion rate and the converted amount are indicative only and inclusive of the bank fee you entered. Issuers may or may not use Mastercard currency conversion rates to bill cardholders and may impose additional fees in connection with foreign currency transactions.

Currency conversion rates are specific to the date and time the issuing bank authorizes the transaction (which generally occurs at the point of sale/interaction). If Mastercard is unable to apply the currency conversion rate at authorization, Mastercard will apply the currency conversion rate at the date and time the transaction is processed. If a transaction is converted by the merchant or ATM operator, Mastercard currency conversion rates will not apply. This will usually occur when you select to pay in your card's currency as opposed to the currency of the merchant or ATM. For more information on the currency conversion rate for purchases in Argentina, please visit: [Mastercard](https://www.mastercard.com.ar.).

Mastercard, in its sole discretion, may restrict usage of Currency Conversion API as Mastercard may deem necessary or appropriate.

## Get Help {#get-help}

### Contact us for technical support. {#contact-us-for-technical-support}