This application was built with Xcode 9 using Swift 4. Make sure to have the Xcode version installed. If not, head to https://developer.apple.com and download the latest version.
The software was supposed to be implemented within 2 hours. Currently, the project took up to 4 hours due to extensive unit testing and the API integration / serialization of http://jsonrates.com/ for current currency exchange rates.
The implementation of the http://jsonrates.com/ API was performed with a free membership and will only cover rudimentary API functions (as required by the Home Code Exercise).
Thus the focus lies on correct API coverage and data serialization, while the UI is kept simple to on fulfill the listed basic requirements.