Turbopack

Definitions

A Rust-based JavaScript bundler developed by Vercel as the successor to Webpack, designed to be dramatically faster through incremental computation and native performance. Turbopack uses a function-level caching architecture where only the code that changed is reprocessed, achieving hot module replacement (HMR) times that remain fast regardless of application size. It is integrated into Next.js as the default development bundler, replacing Webpack for local development. Turbopack's architecture was influenced by Turborepo's task-based caching and Salsa (a Rust incremental computation framework). While production bundling support is still maturing, Turbopack already delivers 10x faster updates than Webpack for large Next.js applications during development, addressing one of the biggest developer experience pain points.
In plain English: A super-fast code bundler written in Rust, built by Vercel to replace Webpack. It makes your code changes appear in the browser almost instantly during development, even for huge applications.
Example: After enabling Turbopack in our Next.js project, hot reload went from 3 seconds to 200 milliseconds. The dev server feels instant now.