It is necessary to develop crypto trading apps with cross-platform compatibility to reach a larger audience. By developing for both iOS and Android with a single codebase, developers can save time and money on development while delivering a similar experience across devices. There are several tools and frameworks that can be leveraged to develop quick and performant crypto trading apps.

React Native
React Native is a very popular cross-platform application development framework. Using JavaScript and React, developers can create apps with native-like performance for Android and iOS. React Native boasts a massive library of pre-built components that facilitate speedy development and easy integration with third-party APIs, which is essential for real-time crypto price feeds and trade execution.

Flutter
Developed by Google, Flutter is one more powerful framework to build natively compiled mobile, web, and desktop applications using a shared codebase. It uses Dart programming language and provides highly customizable widgets to create visually appealing crypto trading apps.

Xamarin
Xamarin, which is owned by Microsoft, uses C# and the.NET framework to create cross-platform applications. It allows for simple integration with native device features, and thus it's perfect for creating high-performance crypto trading applications that require direct mobile hardware manipulation.

API Integration
To support real-time trading, these frameworks are designed to be compatible with RESTful APIs and WebSocket connections for real-time data feeds, trade execution, and portfolio tracking. This enables users to receive real-time price quotes and trade in real-time.

Using these tools, developers can develop rapid and scalable crypto trading apps with enhanced performance and usability across platforms.