Next.js

Next.js is the React framework that powers full-stack web applications. The repository at vercel/next.js is the home of the next npm package along with the Turbopack bundler, the SWC-based compiler, the App Router runtime, the Pages Router runtime, and the supporting CLI and developer tooling that ship as part of every release.

What lives here

This is a pnpm monorepo with four major source areas:

• packages/ — TypeScript and JavaScript packages published to npm. The flagship is packages/next, which is the framework users install with npm install next.
• crates/ — Rust crates that build the SWC-based custom transforms, the Next.js API used by Turbopack, the build orchestration, and the napi/wasm bindings.
• turbopack/ — A git subtree containing the Turbopack bundler crates. This subtree is split out of and merged back into vercel/turborepo periodically.
• test/ — End-to-end, integration, development-mode, production-mode, and unit test suites that exercise both the JavaScript runtime and the Rust pipeline.

Documentation lives in docs/ and is the source for nextjs.org/docs. Examples live in examples/ (more than 200 of them).

Two routers, two pipelines, one framework

Next.js ships two router implementations side by side:

• App Router (packages/next/src/server/app-render/, packages/next/src/client/components/app-router*) — the React Server Components-based router that supports streaming, server actions, partial prerendering, and the new caching primitives.
• Pages Router (packages/next/src/server/render.tsx, packages/next/src/pages) — the original pages/ directory router using getStaticProps / getServerSideProps.

Both routers share the same dev server, route server, image optimizer, and CLI. They build through a unified pipeline in packages/next/src/build/index.ts that supports three bundlers: Turbopack (default), webpack, and rspack.

Quick links

• System architecture — how dev server, build, route server, and rendering fit together
• Getting started — clone, install, build, and run the framework locally
• Glossary — terms used throughout the codebase
• How to contribute — workflows, testing, and conventions
• Codebase by the numbers — size, churn, and language breakdown
• Lore — history of the codebase and major rewrites