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

## FAQ {#faq}

Available to Mastercard issuers in the European Economic Area (EEA). 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 **Enhanced** **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 sandbox. This quota does not affect production. When an issuer includes fixed amount fees on cross-currency transactions, the amount of each individual purchase transaction influences the overall calculated exchange rate; for example, 1 Euro fee on a 10 Euro transaction is 10%, but on a 100 Euro transaction it is only 1%. We recommend that customers call the API each time there is a request from the cardholder using the Issuer user interface.

In addition, customers can call the API a maximum of x2 per day (upon Mastercard rates being updated and ECB rates being updated) per desired currency pair. Internalize the rate information for cardholder presentment until the rates are refreshed the next day.

For more information, please refer to the support articles *What time does Mastercard publish its rates and what is the effective time period for the rates?* \& *What time are the published ECB rates made available through the Enhanced Currency Conversion API?*
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/enhanced-currency-conversion-calculator/documentation/tutorials-guides/#guides) The API supports all reference rates currently published by the European Central Bank (ECB). All currencies are quoted against the euro (base currency)

When neither the transaction currency nor the cardholder billing currency is equal to Euro, a calculated reference rate is derived using the two ECB rates.
ECB reference rates are updated within one hour after the new rates are published by the European Central Bank at 16:00 Central European Time. The ECB publishes reference rates on every working day, except on TARGET closing days.

Please refer to the [ECB website](https://www.ecb.europa.eu/stats/policy_and_exchange_rates/euro_reference_exchange_rates/html/index.en.html)for more details
Effective 19 April 2020, Issuers located in the European Economic Area (EEA) will be required to disclose to their cardholders through an electronic platform (e.g. website, online app, and so on) the % mark-up between their FX rates, including any issuer related fees, and the exchange rate published by the European Central Bank (ECB) for the same currency pair. Issuers can utilize the information included in the API to disclose the required information. Participating issuers can utilize the data retrieved from the Enhanced Currency Converter to develop their own transaction-level requirements, however Mastercard is creating a transaction-level service that will provide participating issuers all of the data elements needed to comply with the April 2021 requirement. The ECB rate information will be made available as of April 19, 2021, in a new subfield of the Authorization message, as an enhancement of the Cross-Border Fee Manager Service. Please contact [currency_converter_team@mastercard.com](mailto:currency_converter_team@mastercard.com) or your Account Manager regarding more information on how to access the Cross Border Fee Manager service. The foreign exchange rate and the converted FX amount are indicative only and inclusive of the bank fee you entered. Issuers may or may not use Mastercard foreign exchange rates to bill cardholders and may impose additional fees in connection with foreign currency transactions.

Foreign exchange rates are specific to the date and time the issuing bank authorizes the transaction (which generally occurs at the point of sale/interaction). For certain transactions, including those authorized prior to August 11, 2020 or submitted to Mastercard for processing nine or more days from the original date of authorization, Mastercard will apply the foreign exchange rate in effect at the date and time Mastercard processes the transaction. If a transaction is converted by the merchant or ATM operator, Mastercard foreign exchange 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.

Mastercard customers must carry out their own legal assessment of the requirements under EU Regulation 518/2019, and how information provided by Mastercard may be used to ensure compliance with these requirements.
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).

## Get Help {#get-help}

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