Basic Information Concerning APK Applications. Smart phones currently nowadays have become very popular and come with a variety of operating systems such as windows, Mac or Android. Android is the most preferred app by smart phone users. Since Android is an open source platform, any manufacturer can install it on their phones. This has made the cost of the devices less than making their operating system or using one that is paid. Various apps are coming up every day, but the most common ones are the android apps. When an app is fully developed it can carry a variety of files and folders. The features of an app are determined by the files and folders it carries. In order for a mobile app to function, an archive with all the necessities is required first. Android package kit is the term used for the archive file. Runnning an app in a mobile phone requires some special data and files that are found in an android package kit. The package kit has a code that determines its capabilities and functions. Classes.index is the technical term for the source code. Manifest file is the other component of the APK. The component provides specifications for permission to the application’s needs, package, it’s flow, signatures, certificates, version codes and SHA-1 Digest. Another important component of the apk is referred to as libs. The element comprises jar files and codes which act as library for the application. Asset is the other element of APK and performs the functions of filing fonts, audios, and texts. The different layout design for android applications are generally defined by the resource component of the APK. Other directories contained in the kit includes META-INF and res. Development of an app requires that it is tested before release into the market. Then an export APK is generated where the ones developing it sign in the app with a coded key. The secret code put by the developers acts as a proof of authority over the app. Users can then access the app in the Google play store after it is uploaded. The android package kit is the one that gets fitted to the mobile gadget when one downloads the app. APK MIRROR is the other online platform that provides clients to access android apps. APK MIRROR is a website where one is allowed to download applications that are available in the Google play store. An account is however not required like in the case of Google play. High security measures are provided so as to provide highly trusted and original apps to the users in the play store during uploading and downloading of apps. The High-security measures include signature authorization and verification of certificates. APK MIRROR offers the ability to download older versions of an app if one is not satisfied with new one.