Turborepo is an open-source build system for JavaScript and TypeScript, written in Rust, from Vercel. It is designed for monorepos, single repositories that hold many packages or apps. In a monorepo each workspace has its own tests, linting and build, so the whole repository may have thousands of tasks.
Turborepo reads the package.json scripts and dependencies already in the repository, plus one turbo.json file that declares the tasks and their order, for example that a package is built only after the packages it depends on. It runs tasks in parallel on all available CPU cores and caches the output of each task. Remote Caching shares those outputs between machines and CI (continuous integration) servers, so work done once is not repeated, and the --affected option runs only the tasks touched by a change. The turbo docs command lets coding agents search the documentation from the terminal.
Turborepo is free and open source under the MIT license. It installs from npm as the turbo package and works with npm, yarn and pnpm.