get data from curency converter api

As user i want to get currency exchange info. given two currencies and amount to convert, as result json with requested data and response like

{"request":{"from": "RUR", "to": "CZK", "amount":10000.0}, response: {"amount": 2 939.16, "currency": "CZK"} }

for any given pair. be able to handle at least 100rps