Lit

Lit is an open-source library for building fast, lightweight web components, now part of the OpenJS Foundation. Built on browser standards, it adds reactive properties, declarative templates, scoped styles, and other features that simplify component development without requiring a custom syntax or compilation. At around 5 KB minified and compressed, Lit is designed to keep bundles small, while updating only the dynamic parts of the interface for efficient rendering.

Lit components are standard custom elements, so they can be used in plain HTML, JavaScript, content management systems, static site builders, or alongside different frameworks. The library’s Shadow DOM-based styling helps isolate component CSS, while reactive properties trigger updates when values change. These capabilities make Lit useful for creating reusable components, cross-framework design systems, and maintainable websites and applications.

The Lit project provides documentation, interactive tutorials, a browser-based Playground, and community channels including Discord, Bluesky, GitHub, and Stack Overflow. Its ecosystem includes projects such as Spectrum Web Components, Carbon Web Components, and UI5 Web Components.