Cryptify is a mobile app for tracking real-time prices of cryptocurrencies. It is a native app for the iOS operating system, i. e. for the Apple iPhone, created in Swift language and Swift UI framework.
Users can track real-time rates, charts showing price movements, trades, and order books. The application offers saving favorite currencies, creating watchlists, sending notifications, or customizing the user interface.
The goal was to create a native mobile app for the iOS operating system, which allow users to easily and quickly track the current cryptocurrency rates. The inspiration was the Apple stock app, which has a similar purpose for stocks. I wanted to create an app that is simpler and easier to use than complicated crypto exchange apps.
The most important feature is displaying the cryptocurrency rates of different pairs of cryptocurrencies. On the Markets screen, users can see a list of tradable pairs at the Poloniex exchange (I use their API as a data source). The app allows to sort the pairs by price, name or daily change. Furthermore, the users can search in the list of pairs.
In addition to the list of all pairs, users have a watch list where they can save pairs of interest. It is also possible to create more lists and set the default list displayed on the home screen after opening the app.
The second most important feature is displaying pair detail. Detail shows current price, daily change, chart, trades, and order book.
The app offers three chart display options - area, line, and candle chart. Next, users can choose the period that the chart represents. The options are All, 10, 5, 2, 1 year, 6, 3, 1 month, week, day, hour, and 30 minutes.
At the bottom of the pair detail, it is possible to toggle between trades and order book. Bids and asks are distinguishable by color.
Last but not least, settings. The settings screen allows users to change the theme (light, dark, system), disable notifications and sounds, and change the app language. The app supports English and Czech.
While developing the app, I experienced several issues. Luckily I was able to solve all of them.
Firstly, I couldn't create a custom toolbar and override Apple's default NavigationView. I had a problem with the placement of the element in the toolbar, and the toolbar didn't expand when rotating the device.
Another issue was the cancellation of API requests. The variable changes triggered a UI refresh that resulted in the cancellation of the pending requests in methods like task or refreshable.
The last issue I'll mention here is decoding API data. The order book endpoint sends an array that contains numbers and also strings. As a strictly typed language Swift cannot have both strings and numbers in one array, so I had to create a special structure that takes both values.
To conclude everything, I am happy with how the app turned out. I managed to implement all the features I planned and many more that came to my mind during the development process. But there will always be new features, which I can add, for instance, cash the data for times without a cellular connection.
The app is ready, but since I don't have permission to use the Poloniex API commercially, it is not published in the App Store.
- XCode 14
- iOS 16.0
