Rosid is a just-in-time server and static site generator written in Node.js. It transforms files on-the-fly before serving them to the browser. Rosid offers two main features: a development server with live reloading and a static site generator. It is lightweight, flexible, and does not force a specific directory structure. Rosid is powered by popular modules like Browsersync and allows you to compile code to static files for hosting anywhere.