What are some alternatives?
When comparing GoNative.io and Thunkable, you can also consider the following products
Website 2 APK Builder - Convert your HTML, CSS, JS and all other web content into an Android App within seconds.
Codefreebnb - Airbnb clone. Written with not one line of code
appenguin - Turn the most complex web application or website to into an Android app in minutes, for free!
MIT App Inventor - MIT App Inventor | Explore MIT App Inventor
AppPresser - Build iOS/Android apps using WordPress with AppPresser.
Android Studio - Android development environment based on IntelliJ IDEA