Android SDK (Software Development Kit) , which is used to create Android apps for the Android operating system or platform. The Android SDK contains the source code, sample projects , development tools , emulators and libraries needed to build Android projects. The library can be used to create various Android apps. Although the Android application is written in Java programming language, it is built with the help of Android SDK. An important issue in the API on Android. It is good for those who use Android phone to know about it. What is API , its effectiveness or what , is discussed in detail below.