# Nextjs Turbopack

> Next.js 16+ and Turbopack — incremental bundling, FS caching, dev speed, and when to use Turbopack vs webpack.

- Skill: `anantha-236/nextjs-turbopack` (Agent Skill)
- Install (CLI): `npx skillmds add anantha-236/nextjs-turbopack`
- Raw SKILL.md: https://api.skillmd.com/api/skills/anantha-236/nextjs-turbopack/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Web & Frontend
- Author: Anantha-236 (https://skillmd.com/u/anantha-236)
- Updated: 2026-08-19
- Page: https://skillmd.com/skills/anantha-236/nextjs-turbopack

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# Next.js and Turbopack

Next.js 16+ uses Turbopack by default for local development: an incremental bundler written in Rust that significantly speeds up dev startup and hot updates.

## When to Use

- **Turbopack (default dev)**: Use for day-to-day development. Faster cold start and HMR, especially in large apps.
- **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).
- **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.

Use when: developing or debugging Next.js 16+ apps, diagnosing slow dev startup or HMR, or optimizing production bundles.

## How It Works

- **Turbopack**: Incremental bundler for Next.js dev. Uses file-system caching so restarts are much faster (e.g. 5–14x on large projects).
- **Default in dev**: From Next.js 16, `next dev` runs with Turbopack unless disabled.
- **File-system caching**: Restarts reuse previous work; cache is typically under `.next`; no extra config needed for basic use.
- **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).

## Examples

### Commands

```bash
next dev
next build
next start
```

### Usage

Run `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.

## Best Practices

- Stay on a recent Next.js 16.x for stable Turbopack and caching behavior.
- If dev is slow, ensure you're on Turbopack (default) and that the cache isn't being cleared unnecessarily.
- For production bundle size issues, use the official Next.js bundle analysis tooling for your version.