APK (Android Package Kit)

APK (Android Package Kit) is a file format for applications used on the Android operating system. APK files are compiled with Android studios, which is the official integrated development environment (IDE) for the creation of Android software.

The APK file contains all the software programs code and assets. Developers creating apps for use on Android devices need to compile their applications in APK format before uploading the official marketplace of Google Play to Google Play. APK files for Google Play must be less than 100 MB in size. To help developers with this limit, Google Play will host two APK expansion files for any additional content required for their application. The APK expansion file is used to store media files, high-fidelity graphics, or other large assets which will cause the APK to exceed the size limit.

APK files can be distributed directly to other Android users for installation on their devices. Android users can allow their device to install an unknown application if they want to access APK files from another source and install them directly. Android users may wish to install an APK directly if they are testing an unpublished version of the Beta application, or due to device restriction, unable to download the app from Google Play.