Ionic can get you the most code sharing. Ionic uses a web view to render the UI so it will never get you the same as a native UI, but it is actually really good

Ionic can get you the most code sharing. Ionic uses a web view to render the UI so it will never get you the same as a native UI, but it is actually really good. Expect a few delays here and there, though. Make sure to try it out on the oldest phone you plan on supporting to see if you’re okay with the performance before moving forward. Ionic will get you the most code sharing. React Native is a great for cross platform iOS and Android native. If you want code sharing across native app and web app, look into ReactXP, or come up with your own code sharing technique, which apparently @sdcookie’s team did. Titanium from Appcelerator also supposedly targets Native and Web. Also consider focusing your efforts on native and not doing a web app. RobinHood stock trading app went a long ways without having a web app. Just throwing that out there.