Preact

Preact is a fast, lightweight alternative to React created by Jason Miller in 2015, providing the same component-based API and virtual DOM architecture in just three kilobytes of gzipped JavaScript, over forty times smaller than React, enabling web applications to achieve React-like developer experience with dramatically faster load times, lower memory usage, and better performance on mobile devices and slow connections, adopted by companies including Etsy, Uber, Gazette, andIBM for performance-critical web applications. The API compatibility means existing React knowledge and patterns transfer directly, with components defined as functions or classes, JSX for markup, hooks for state management, and props for component communication, while the compatibility layer through preact-compat enables running existing React components and ecosystem libraries including React Router, Redux, and React Helmet without modification. The three kilobyte footprint includes the entire rendering engine, virtual DOM diffing, event system, and component lifecycle, with tree shaking and modern bundlers further reducing the effective size to only the features actually used, making it ideal for progressive enhancement, widget embedding, performance-sensitive landing pages, and mobile web applications where every kilobyte matters. The performance advantages extend beyond size, with Preact implementing optimized virtual DOM diffing algorithms, efficient event delegation, and minimal overhead per component, benchmarking faster than React in render, update, and mount operations while using less memory. The preact-compat alias enables drop-in replacement. The hooks API matches React. The preact-render-to-string provides SSR. The signals primitive provides fine-grained reactivity. Designed for frontend developers prioritizing bundle size and performance.