This document introduces several open source projects that provide building blocks for developing Internet of Things (IoT) solutions, including protocols, tools, frameworks and services. It describes projects like Paho, Mosquitto, Kura and Wakaama that implement common IoT protocols and provide platforms for building sensor networks, gateways and device management. The document envisions that future IoT development will move towards a model where IoT devices function more like the cloud or fog computing.