Install and back up your applications regardless of format What is APK Installer for? APK Installer is a free tool that allows you to install those Android applications whose formats are not recognized by the default package installer included with the operating system. The tool uses a standard XAPK build to support Google's new APK distribution system called APK Split. This application works in two directions, so you can backup installed applications and install your own copies of applications on your smartphone, regardless of the packaging format.