While I was traveling, I was looking for a currency converter app that would satisfy me and wouldn't be packed with ads. After testing most of the apps in the category I saw an opportunity to create my own converter.
The goal was to keep the design as native as possible and focus on user interaction. The app should be reliable in situations where you need it most.
My main idea was to create an input view that the user could hide or unhide at will. A sheet component was perfect for this kind of interaction, but the default numpad is not fits well. I recreated the standard keyboard behavior in my custom one, so you never feel the difference.
Country flags for all supported currencies have been unified and adapted for square format. This helped to achieve cohesive look throughout the app.
It's crucial for travel apps to work offline. In Currency, downloaded exchange rates are stored on your device. To keep the app free and offload API requests, I added 1 hour delay between retrieving up-to-date rates.
The currencies you choose and their order are synced between your devices via iCloud.