Babel REPL vs Turbopack

Babel REPL has no write-up on Specifiction yet; its figures are above.

Turbopack is an incremental JavaScript and TypeScript bundler written in Rust and built into Next.js. It supports the Pages Router and App Router for local development and is the default bundler in Next.js for basic use without configuration. It parallelizes work across CPU cores, caches results at the function level and persists them between runs. Lazy bundling processes only what the development server requests, which can reduce initial compile time and memory use. Its support includes JavaScript, TypeScript, ECMAScript, CommonJS, ESM and Babel configuration detection in Next.js 16, along with JSX, Fast Refresh and React Server Components for the App Router. CSS support includes global CSS, CSS Modules, nesting, PostCSS and Sass/SCSS, but not custom Sass functions. It also handles static image and font imports, JSON, aliases and custom extensions. Native bindings are available for Linux, macOS and Windows. Turbopack is included in Next.js with no separate price stated. It does not perform TypeScript type checking, and it does not support webpack plugins.