uv vs Yarn

uv is a Python package and project manager for Linux, macOS, and Windows. Written in Rust, it manages dependencies and environments, with lockfiles and workspaces, and can install, list, pin, or uninstall Python versions. It also runs scripts with dependencies and runs or installs command-line tools from Python packages. Its pip-compatible interface is intended to cover work done by tools such as pip, pip-tools, pipx, poetry, pyenv, twine, and virtualenv, though its commands do not exactly match those tools. The documentation describes uv as 10–100x faster than pip. It supports source distributions, wheels, requirements.txt, and pylock.toml, as well as offline installation and private registry authentication. For package selection, its default first-index strategy limits candidates to the first index where a package is found. Credentials are not stored in uv.lock, but uv currently stores them in a plaintext file; native system secret storage is an experimental preview. The free plan is free.

Yarn is a package manager and project manager for JavaScript projects, serving uses from simple projects to industry monorepos. It resolves dependencies, maintains lockfiles and provides workspaces that install and link packages within a project. Modern Yarn uses Plug'n'Play by default, generating a Node.js loader file instead of a typical node_modules folder; users can choose node_modules or pnpm-style symlink installs instead. Yarn caches installed packages and shares them among projects on the same machine. Its offline mirror and zero-installs workflow can keep cached packages in a repository and reduce reliance on the npm registry. Plugins can extend resolvers, fetchers, linkers, commands and lifecycle hooks. Generated editor SDKs and settings support VSCode, Vim, Emacs and Neovim. Yarn runs on Linux, macOS and Windows and is free, with no paid plans or usage limits stated. Its documentation notes that React Native and Expo require typical node_modules installs. Yarn does not run audits during installation by default; users can run yarn npm audit separately.