Node-RED is an open-source visual programming tool that simplifies event-driven application development, automation workflows, and integration of various services and devices using Node.js. It offers a browser-based flow editor with a user-friendly interface for connecting nodes to create flows by dragging and dropping elements on the canvas. The tool has gained popularity due to its versatility in diverse domains such as IoT, home automation, data processing, and integration projects. Its features include visual programming, rich node library, flow-based programming, accelerated prototyping, optimized for event-driven architectures, active community support, and system requirements that include Node.js and npm.