App Builder allows you to create your own apps.
You can publish your apps on Google Play.
Simple things can be done without any coding.
For more complex things the coding is done in JavaScript or Java.
You can also earn money by integrating AdMob ads in your app. Both banner ads and interstitial ads are supported. This can be done with no coding at all.

This is much easier than Android Studio, and it does not require a desktop computer.

Features:
- Full access to the Android API.
- Simple things can be done without coding.
- Coding is done in JavaScript or Java.
- Share the APK file or publish your app on Google Play Store.
- Editor with syntax highlighting (HTML, CSS, JavaScript, Java, JSON, XML) and code folds.
- Standard Android build tools are used.
- You can add the dependencies to include libraries from Maven or other repositories.
- Logcat viewer allows you to see system messages, which are useful for debugging.
- Support for Android App Bundle (AAB) format.

A few example apps to use as a starting point:
- AdMob: demonstrates the use of banner ads and interstitial ads, and also displays your device ID (which you need to mark your own device as a test device per AdMob policies).
- Billing: shows how to use in-app billing.
- Camera: a simple app which shows, among other things, how to request permissions at run-time.
- Chats: a public chats app, a rather complex example.
- Clock Widget: yes, you can create app widgets (the things that you put on your home screen, like clock and weather).
- Dialogs: shows how to use dialogs.
- Editor: a simple editor app.
- Favorite Music: an audio player packaged with a playlist.
- Feedback: send messages from your app back to you, the developer.
- HTML app: a template for an HTML-based app.
- Image Gallery: an app that packages photos inside the app.
- Navigation Drawer: shows how to setup a navigation drawer and corresponding views.
- Reminder: demonstrates how to use the AlarmManager and receivers.
- Take Photo: shows how to take photos and use them in your app.
- Text-to-Speech.
- Threads: demonstrates the use of threads.
- ViewPager: shows how to setup a ViewPager (a view that displays other views as "pages" which can be traversed by the "swiping" gesture.
- Website App: a template for an app that shows a website in a WebView.
- Website App with AdMob: Same as above, but also shows an AdMob banner and interstitial ads.

One approach to Android app design is to use the existing HTML/CSS/JavaScript code and wrap it as an app. This can easily be done in App Builder. If you just need to wrap a website URL into an app, App Builder will do it for you in minutes without any coding.

App Builder is also a great tool for learning programming in JavaScript and Android app design.

Without subscription, you have access to most features, but your apps will run only on the device they were built.
Subscription allows you to build apps that do not have this restriction. Also, some features of App Builder only available to users with subscription.

There are quite a few apps on Google Play that claim to be an "App Builder" or "App Maker" or "App Creator" etc. They don't actually allow to create anything functional. They merely allow to fill in a template, choose some options, type in some text, add some pictures, and that's it.
App Builder, on the other hand, allows you to do almost anything a native Android app can do. Simple things can be done with no coding at all, but more complex business logic or app feature may require some coding in JavaScript or Java.

Support group: https://www.facebook.com/groups/AndroidAppBuilder/