Webpack is an open-source JavaScript module bundler designed to process modern web applications by building a dependency graph from one or more entry points and outputting optimized static assets. It takes modules with dependencies—such as JavaScript, CSS, images, and other resources—and compiles them into bundles that can be efficiently served to browsers.

At its core, webpack analyzes a project’s module structure starting from defined entry points, recursively resolves all imported dependencies, and transforms them into one or more output bundles. This enables developers to write modular code using ES Modules, CommonJS, or AMD while webpack handles packaging and optimization for production or development environments.

Webpack extends beyond simple bundling through its loader and plugin system. Loaders allow preprocessing of files (such as transpiling TypeScript or JSX, or importing CSS), while plugins enable deeper customization such as code minification, environment variable injection, and asset optimization. It also supports advanced features like code splitting, lazy loading, and hot module replacement for improved performance and developer experience.

It is widely used in modern frontend ecosystems including React, Vue, and Angular, and serves as a foundational tool for building scalable single-page applications, progressive web apps, and complex multi-page web systems.

Key features include:

• Dependency graph-based module bundling
• Support for JavaScript, TypeScript, CSS, images, and more via loaders
• Plugin system for extensibility and build customization
• Code splitting and lazy loading for performance optimization
• Hot Module Replacement for faster development workflows
• Asset optimization including tree shaking and minification

Common use cases include:

• Bundling frontend web applications
• Optimizing assets for production
• Managing complex module dependencies
• Building single-page applications
• Enabling modern JavaScript development workflows

Webpack is developed and maintained as an open-source project by the webpack community, originally created by Tobias Koppers.