Returns an exchange rate between base and target currencies for a given date
Basic authentication header of the form Basic <api_key>, where <api_key> is your api key.
Base currency of the exchange rate
Target currency of the exchange rate
Date the exchange rate is requested for. If omitted, defaults to today
default response
"USD"
"USD"
Exchange rate between base and target currency
Effective date of the exchange rate. E.g., rate requested on Saturday will have the effective date Friday
Date the exchange rate is requested for