Three most popular solutions:
React Native:
React Native - A cross-platform native framework developed by Facebook
Apps build with React Native https://facebook.github.io/react-native/showcase
https://reactnative.dev/docs/debugging - debugger
Why AirBnb is moving away from React Native - https://www.theimmigrantprogrammers.com/p/why-airbnb-dumped-react-native?s=r
Tools suitable for automating React Native
https://medium.com/@ronak8036/react-native-testing-tools-f38d715adb57
Pay attention to https://www.cypress.io/how-it-works/!
Flutter:
Flutter - A cross-platform native framework developed by Google
"Flutter is an open-source UI software development kit created by Google. It is used to develop applications for Android, iOS, Windows, Mac, Linux, Google Fuchsia and the web."
Cupertino Widgets - Flutter - How the IOS apps look with Flutter
Apps build with Flutter - https://flutter.dev/showcase
Flutter Driver for automation testing - https://flutter.dev/docs/cookbook/testing/integration/introduction
Xamarin:
"Xamarin is a Microsoft-owned San Francisco-based software company founded in May 2011 by the engineers that created Mono, Xamarin.Android and Xamarin.iOS, which are cross-platform implementations of the Common Language Infrastructure and Common Language Specifications"
Example - Cinemark Theatres app
Native, React Native, Flutter and More - By Barlow Tucker droidcon San Francisco 2019
Adding Flutter to Your Android App - By Matt Carroll droidcon San Francisco 2019