Explore connected device development using contract-based approaches in this conference talk from GOTO Aarhus 2013. Dive into the Feuerlabs Exosense framework, designed for managing connected devices with a focus on rapid prototyping and scalability. Learn about the conceptual approach and follow an Erlang-based embedded application prototype for in-vehicle performance monitoring and remote control. Discover how to quickly produce a working end-to-end demonstration while preparing for deployment, support, and upgrades. The talk covers topics such as device management, server setup, project schematics, registration processes, specifications, RPC requests, helper functions, initialization code, CPU usage, open-source libraries, GPIO, package management, file transfer, and SMS functionality. Gain insights into creating hacker-friendly frameworks suitable for both rapid development and long-term evolution in massive-scale deployments.