Api.Forex.Sharp
Open a free account on https://api.forex and get an api key
string ApiForexKey = "{YourKey}"
DailyRates ForexRates = await ApiForex.GetRate(ApiForexKey);
Convert the rates to an other currency. Example: convert 5 Thai bahts in Euros
decimal test = ForexRates.Convert("THB", "EUR", 5)