Hadoop YARN is the next generation computing platform in Apache Hadoop with support for programming paradigms besides MapReduce. In the world of Big Data, one cannot solve all the problems wholly using the Map Reduce programming model. Typical installations run separate programming models like MR, MPI, graph-processing frameworks on individual clusters. Running fewer larger clusters is cheaper than running more small clusters. Therefore,_leveraging YARN to allow both MR and non-MR applications to run on top of a common cluster becomes more important from an economical and operational point of view. This talk will cover the different APIs and RPC protocols that are available for developers to implement new application frameworks on top of YARN. We will also go through a simple application which demonstrates how one can implement their own Application Master, schedule requests to the YARN resource-manager and then subsequently use the allocated resources to run user code on the NodeManagers.