Context

I need a bundler and development server for the Next.js application. The standard default for Next.js has long been Webpack. However, as the application grows, Webpack's build times and HMR (Hot Module Replacement) latency can increase linearly, slowing down the feedback loop.

Requirements:

• Velocity: Instant startup and HMR are critical for maintaining flow.
• Compatibility: Must work seamlessly with Next.js App Router and server components.

Alternatives considered:

• Webpack: The stable default. It is "boring" and reliable but significantly slower.
• Vite: Ultra-fast, but incompatible with the Next.js App Router dev server (which requires deep integration for React Server Components). Next.js cannot simply "run on Vite".

Decision

I decided to use Turbopack (via next dev --turbopack).

Turbopack is Vercel's Rust-based successor to Webpack. It is designed specifically to handle the complexity of React Server Components with extreme performance.

Consequences

Pros

• Performance: Written in Rust, it is orders of magnitude faster than Webpack for startup and HMR.
• Lazy Bundling: It only compiles the pages/components currently requested, meaning a large project starts as fast as a small one.
• Easy Revert: It is purely an opt-in flag. If issues arise, I can simply remove --turbopack and fall back to Webpack immediately.
• Future Proof: It is the designated future of the Next.js compiler infrastructure.

Cons

• Stability: While stable for development in recent Next.js versions, it may still have edge-case bugs compared to the decade-old Webpack.
• Plugin Ecosystem: It does not support the full range of Webpack loaders/plugins (though most modern Next.js apps don't need custom Webpack config).