Session presented at the 6th IndicThreads.com Conference on Java held in Pune, India on 2-3 Dec. 2011. http://Java.IndicThreads.com --- Historically writing correct concurrent, scalable and fault-tolerant applications has been very hard. Akka is an attempt to simplify writing concurrent, scalable and highly available software for the JVM. Akka has an API both for Scala and Java. Akka uses the Actor Model together with Software Transactional Memory (STM) to raise the abstraction level. For fault-tolerance it adopts the “Let it crash” model which help in building self healing always on systems. The presentation walks through the Akka features for building a web scale system. We would look at a real world case study in which Inphina developed a web scale framework using Akka which is capable of processing 150 million streaming messages a day. We would discuss the architecture and key design decisions. http://www.indicthreads.com/9241/scalable-applications-with-akka/