Composer vs Yarn

Composer manages dependencies for PHP projects, installing and updating the libraries each project declares. By default, it keeps those dependencies in a directory within the project, and it can also manage a global project. It resolves dependencies and supports lockfiles, workspaces, private registry authentication, and offline installation. Packagist is its default package source; custom Composer, version-control, and local-path repositories are also supported. Composer integrates with Fossil, Git, Mercurial, Perforce, and Subversion. It can be installed locally or as a system-wide executable on Windows, Linux, and macOS. The latest version requires PHP 7.2.5 or later; the 2.2.x LTS line supports PHP 5.3.2 and later. Its audit command checks installed packages for security advisories, abandoned packages, malware flags, and other dependency policies. Composer is free under the MIT license. Plugins and scripts can run with the user's permissions, so the project advises against running Composer as root with untrusted packages.

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.