This document discusses using Akka for IoT applications. It describes a demo application called Where on Earth (WoE) that uses Akka microservices to handle IoT device telemetry and state changes in a reactive, elastic and resilient manner. The WoE application demonstrates using Akka Cluster to distribute services, CQRS to separate commands from queries, and event sourcing with Akka Persistence to maintain state. It estimates future IoT data rates could reach thousands of state changes per second, showing the need for scalable and high performance architectures like Akka.