The API found at https://free.currconv.com/api/v7/convert?apiKey=sample-api-key&q=USD_PHP&compact=y could be used on an E-commerce website. A user can use the currency converter to calculate the currency exchange rate. For example, a user wants to purchase something from Japan which is Japanese Yen to US dollars. Using the currency API converter, it would look up the current exchange rate for JPY to USD then calculate the cost to US dollars. This currency converter API is very useful for shoppers to calculate the exact cost in their currency.
Link to the proof-of-concept work: http://misdemo.temple.edu/tuc53942/Currency%20Converter%20API_files/