How Does an APK File Work?

APK, APK Files

If you have ever downloaded an app on your Android device, then you must be familiar with the term APK. An APK file is basically the installation package of an Android app. In this article, we will explore how does an APK file work and what are its components.

What is an APK File?

An APK file stands for Android Package Kit. It is a file format that contains all the necessary files and information required to install and run an Android app on your device. When you download an app from the Google Play Store, it automatically downloads and installs the APK file on your device.

Components of an APK File

An APK file consists of various components that make up an Android app. Let’s take a look at them:

1. Manifest File

The manifest file is a crucial component of an APK file as it contains information about the app’s name, version, permissions required to run, activities, services, and receivers. It acts as a blueprint for the entire app.

2. Resources

The resources folder consists of all the images, layouts, strings, and other resources used in the app. It makes up most of the size of the APK file.

3. Classes.dex

Classes.dex is a compiled code that contains all the Java classes used in the app.

4. Libs

Libs or libraries are additional files required by some apps to run properly. They contain native code that can only be run on specific devices.

How Does An APK File Work?

When you download an app from Google Play Store or any other source, it downloads and installs its corresponding APK file on your device. Once installed, when you click on the app icon from your home screen or app drawer, it initiates a series of actions.

First, the Android operating system extracts the APK file and installs it on your device. Then, it checks the manifest file to determine the app’s name, version, and permissions required to run. Once verified, it loads all the resources and libraries required by the app.

Finally, it runs the code present in classes.dex file using the Android Runtime environment. The app then displays its UI and starts executing its functionalities.


In conclusion, an APK file is a crucial component of any Android app that contains all the necessary files and information required to install and run an app on your device. It consists of various components like manifest file, resources folder, classes.dex file, and libraries. Understanding how APK files work can be helpful in troubleshooting various issues related to Android apps.