Node-RED is an open-source, low-code, visual programming tool that allows users to rapidly glue together different types of hardware and software. It provides a number of pre-built nodes that enable non-developers to create custom integrations and automations using a visual interface, while also allowing developers to write their own custom nodes using JavaScript or external services. The tool has a large community with over 14,000 stars on GitHub and a library of over 3,000 pre-built nodes and 2,000 customizable flows that cover many common use cases. Node-RED consists of core components including nodes, which are triggered by receiving a message object from a previous node or an external event, and flows, which are containers for organizing a sequence of nodes. The tool also provides features such as context, messages, and debug nodes to help users develop and troubleshoot their workflows. With its ease of use and versatility, Node-RED is suitable for a wide range of applications, including IoT projects, smart home automation, event processing, and data visualization and analysis.