This document discusses programming IoT gateways using JavaScript with the macchina.io toolkit. Macchina.io is an open source modular toolkit for building embedded IoT applications that connect sensors, devices, and cloud services. It uses C++ for performance but includes a JavaScript interface. The document provides an overview of macchina.io and its components, demonstrates how to use JavaScript to access sensors and cloud services, and provides an example of logging sensor data to a database and sending SMS alerts based on sensor readings.