Lit

Lit is a library for building fast, lightweight web components using the web platform standards. Created by Google and now a project of the OpenJS Foundation, Lit adds just what developers need on top of the native Web Components APIs: reactivity, declarative templates, and a handful of carefully designed features that reduce boilerplate while staying close to the platform. Each Lit component is a native web component, meaning it works anywhere HTML works, with any framework or none at all, making Lit ideal for building shareable components, design systems, and future-ready applications. The library weighs approximately 5 kilobytes minified and compressed, keeping bundle sizes small and loading times short. Rendering is blazing fast because Lit touches only the dynamic parts of the UI when updating, without rebuilding a virtual tree and diffing it with the DOM. Reactive properties trigger automatic re-rendering when values change. Declarative templates use tagged template literals with efficient native browser template parsing. Scoped CSS provides style encapsulation through Shadow DOM. Support for async rendering, directives for custom template behavior, context protocol for cross-tree data sharing, and decorators for TypeScript ergonomics are all built in. Lit Labs provides experimental features including SSR support, React wrappers, and animation helpers. The ecosystem includes hundreds of open source component libraries built on Lit including Material Web Components, Lion from ING, and Microsoft Fast. Used in production by Adobe, IBM, SAP, Cisco, Alaska Airlines, Reddit, ING, Pepsi, and PlayStation. Open source under the BSD 3-Clause license.