Turbopack is an open-source tool designed to improve the developer experience for next.js developers. It was built by combining learnings from optimization work in the Next.js ecosystem, leveraging Rust-based SWC and creating two layers of interoperability: a core engine for common tasks like caching and invalidation, and a bundler handling CSS, static assets, Wasm, images, fonts, and more. Turbopack's alpha release aims to provide faster build times, hot reload, and remote caching capabilities, allowing developers to rebuild large sites in seconds for minor changes. The tool is designed to be purpose-built with improving the developer experience, and its future plans include supporting other frameworks through a plug-in architecture and providing deeper insights into build optimization opportunities.