Now days, to live in a very much digitalized smart world, everyone is in need of different electronic gadgets, which are so smart to give any required information immediately. This smartness sounds significant because of Internet and Android Technology, which births to smarts gadgets like Smart Phones, Smart Hubs, Smart TV"s etc., which are, used everywhere. Internet of Things (IoT) also has a boom in the industry that helps to provide the smartness for different things. To provide the smartness for the different gadgets, the Android is supportive platform available which give the challenge for the App Developers to develop the Android based Apps for IoT. With respective of this, in this paper, a review study is done for understanding the IoT, its tools and technologies required to develop the Android based app for IoT.