Disclaimer: Never try to reverse engineer apps, which are not developed by you. I’m not responsible for any damage you may cause to third-party developers using this tutorial, I insist that you should use this knowledge only to audit your own apps! So, your Android app was pirated? You have Google in-app purchases, but someone published a full paid version for free on pirating websites? How is it even possible? Let’s try to understand and try to decompile APK file. Here is the guide. Not for pirates or hackers, but for developers — so you will know better your app’s security weak sides. In this tutorial, I will be using Mac OS X, but the tools I’m using are multi-platform — and you can install them also on Linux and even maybe Windows. To start with, you will obviously need the APK file of the app you want to reverse engineer. As it is....