Nextjs Turbopack

1---2name: nextjs-turbopack3description: Next.js 16+ and Turbopack — incremental bundling, FS caching, dev speed, and when to use Turbopack vs webpack.4origin: ECC5---6 7# Next.js and Turbopack8 9Next.js 16+ uses Turbopack by default for local development: an incremental bundler written in Rust that significantly speeds up dev startup and hot updates.10 11## When to Use12 13- **Turbopack (default dev)**: Use for day-to-day development. Faster cold start and HMR, especially in large apps.14- **Webpack (legacy dev)**: Use only if you hit a Turbopack bug or rely on a webpack-only plugin in dev. Disable with `--webpack` (or `--no-turbopack` depending on your Next.js version; check the docs for your release).15- **Production**: Production build behavior (`next build`) may use Turbopack or webpack depending on Next.js version; check the official Next.js docs for your version.16 17Use when: developing or debugging Next.js 16+ apps, diagnosing slow dev startup or HMR, or optimizing production bundles.18 19## How It Works20 21- **Turbopack**: Incremental bundler for Next.js dev. Uses file-system caching so restarts are much faster (e.g. 5–14x on large projects).22- **Default in dev**: From Next.js 16, `next dev` runs with Turbopack unless disabled.23- **File-system caching**: Restarts reuse previous work; cache is typically under `.next`; no extra config needed for basic use.24- **Bundle Analyzer (Next.js 16.1+)**: Experimental Bundle Analyzer to inspect output and find heavy dependencies; enable via config or experimental flag (see Next.js docs for your version).25 26## Examples27 28### Commands29 30```bash31next dev32next build33next start34```35 36### Usage37 38Run `next dev` for local development with Turbopack. Use the Bundle Analyzer (see Next.js docs) to optimize code-splitting and trim large dependencies. Prefer App Router and server components where possible.39 40## Best Practices41 42- Stay on a recent Next.js 16.x for stable Turbopack and caching behavior.43- If dev is slow, ensure you're on Turbopack (default) and that the cache isn't being cleared unnecessarily.44- For production bundle size issues, use the official Next.js bundle analysis tooling for your version.