Nextjs15 Turbopack FAQ & Answers

Run with --turbo flag (stable in Next.js 15): next dev --turbo or add to package.json: 'dev': 'next dev --turbo'. Performance improvements: 76.7% faster local server startup, 96.3% faster Fast Refresh code updates, 45.8% faster initial route compile. Turbopack stable for development as of October 2024 (Next.js 15). Built with Rust, 2x-5x faster than webpack. Benefits: instant feedback during development, faster hot module replacement, improved developer experience. Production: over 50% of Next.js 15 dev sessions use Turbopack. Configure in next.config.js: export default { turbopack: { rules: {...}, resolveAlias: {...} } }. Previous experimental.turbo config deprecated - use top-level turbopack key. Migration codemod: npx @next/codemod@latest next-experimental-turbo-to-turbopack. Works with all Next.js features: App Router, Server Components, streaming.

Turbopack supports webpack loaders but NOT plugins: turbopack: { rules: { '.svg': { loaders: ['@svgr/webpack'], as: '.js' } } }. Uses loader-runner for loader execution. Limitations: only JavaScript-returning loaders supported (no CSS/image loaders), core subset of loader API only. Webpack plugins unsupported - must find Turbopack alternatives or use webpack fallback. Built-in support eliminates common loaders: css-loader, postcss-loader, babel-loader (for @babel/preset-env) - Turbopack handles natively. Rspack alternative: better webpack compatibility (96% test pass rate) with Rust performance via next-rspack adapter. Production: audit dependencies - Turbopack ecosystem still maturing. Migration: test custom loaders thoroughly, expect some incompatibilities. Turbopack uses redesigned architecture reducing migration cost for webpack-dependent projects. Check Turbopack docs for supported loader features.

Timeline: Next.js 15.3 (April 2025) alpha, 15.4 (July 2025) passes 8298 tests, 15.5 (August 2025) beta, Next.js 16 (2025) stable and default. Use: next build --turbopack for production. Not recommended for mission-critical apps in 15.5 (beta). Performance: 28-83% faster builds (depends on cores), comparable/better FCP/LCP/TTFB metrics vs webpack, similar/smaller JS/CSS bundles. Production stats: powers vercel.com, v0.app, nextjs.org - 1.2B requests served. Configuration: turbopack key in next.config.js. Migration from 15.2.x: npx @next/codemod@latest next-experimental-turbo-to-turbopack. Benefits: faster CI/CD pipelines, reduced build times, production-ready performance. Recommendation: test thoroughly before deploying critical apps, use webpack fallback if issues arise. Next.js 16 makes Turbopack default for all new projects.

Common error: 'Webpack is configured while Turbopack is not' - caused by webpack-specific config (crypto fallbacks, aliases). Fix: remove webpack config or add equivalent turbopack config: turbopack: { resolveAlias: { crypto: 'crypto-browserify' } }. Windows issue: 'turbopack issue with nextjs15' - wrong Node.js architecture (x86 vs x64). Fix: install x64 Node, delete .next and node_modules, run npm install. Production build fails: webpack_require error. Fix: delete .next, rebuild with npm run build. Config migration error: experimental.turbo deprecated. Fix: run codemod npx @next/codemod@latest next-experimental-turbo-to-turbopack. Browserslist incompatibility: modern syntax not transpiled. Workaround: use webpack until fixed or adjust target browsers. Production: start with webpack, gradually test Turbopack, use webpack fallback for blocked features. Check GitHub issues for known problems. Turbopack maturing - expect some rough edges in 15.x.

Run with --turbo flag (stable in Next.js 15): next dev --turbo or add to package.json: 'dev': 'next dev --turbo'. Performance improvements: 76.7% faster local server startup, 96.3% faster Fast Refresh code updates, 45.8% faster initial route compile. Turbopack stable for development as of October 2024 (Next.js 15). Built with Rust, 2x-5x faster than webpack. Benefits: instant feedback during development, faster hot module replacement, improved developer experience. Production: over 50% of Next.js 15 dev sessions use Turbopack. Configure in next.config.js: export default { turbopack: { rules: {...}, resolveAlias: {...} } }. Previous experimental.turbo config deprecated - use top-level turbopack key. Migration codemod: npx @next/codemod@latest next-experimental-turbo-to-turbopack. Works with all Next.js features: App Router, Server Components, streaming.

Turbopack supports webpack loaders but NOT plugins: turbopack: { rules: { '.svg': { loaders: ['@svgr/webpack'], as: '.js' } } }. Uses loader-runner for loader execution. Limitations: only JavaScript-returning loaders supported (no CSS/image loaders), core subset of loader API only. Webpack plugins unsupported - must find Turbopack alternatives or use webpack fallback. Built-in support eliminates common loaders: css-loader, postcss-loader, babel-loader (for @babel/preset-env) - Turbopack handles natively. Rspack alternative: better webpack compatibility (96% test pass rate) with Rust performance via next-rspack adapter. Production: audit dependencies - Turbopack ecosystem still maturing. Migration: test custom loaders thoroughly, expect some incompatibilities. Turbopack uses redesigned architecture reducing migration cost for webpack-dependent projects. Check Turbopack docs for supported loader features.

Timeline: Next.js 15.3 (April 2025) alpha, 15.4 (July 2025) passes 8298 tests, 15.5 (August 2025) beta, Next.js 16 (2025) stable and default. Use: next build --turbopack for production. Not recommended for mission-critical apps in 15.5 (beta). Performance: 28-83% faster builds (depends on cores), comparable/better FCP/LCP/TTFB metrics vs webpack, similar/smaller JS/CSS bundles. Production stats: powers vercel.com, v0.app, nextjs.org - 1.2B requests served. Configuration: turbopack key in next.config.js. Migration from 15.2.x: npx @next/codemod@latest next-experimental-turbo-to-turbopack. Benefits: faster CI/CD pipelines, reduced build times, production-ready performance. Recommendation: test thoroughly before deploying critical apps, use webpack fallback if issues arise. Next.js 16 makes Turbopack default for all new projects.

Common error: 'Webpack is configured while Turbopack is not' - caused by webpack-specific config (crypto fallbacks, aliases). Fix: remove webpack config or add equivalent turbopack config: turbopack: { resolveAlias: { crypto: 'crypto-browserify' } }. Windows issue: 'turbopack issue with nextjs15' - wrong Node.js architecture (x86 vs x64). Fix: install x64 Node, delete .next and node_modules, run npm install. Production build fails: webpack_require error. Fix: delete .next, rebuild with npm run build. Config migration error: experimental.turbo deprecated. Fix: run codemod npx @next/codemod@latest next-experimental-turbo-to-turbopack. Browserslist incompatibility: modern syntax not transpiled. Workaround: use webpack until fixed or adjust target browsers. Production: start with webpack, gradually test Turbopack, use webpack fallback for blocked features. Check GitHub issues for known problems. Turbopack maturing - expect some rough edges in 15.x.