package.json File — Node.js Package Manifest

package.json is the manifest file for Node.js projects, serving as the central configuration for npm (Node Package Manager) and the broader JavaScript ecosystem. The file uses JSON to define the project's name, version, description, entry points (main, module, exports), scripts (build, test, start, deploy), dependencies, devDependencies, peerDependencies, engines (Node.js version requirements), and metadata for publishing to npm. The scripts section defines command aliases that are run with npm run or yarn, forming the project's task runner interface. Dependencies use semantic versioning with range specifiers (^, ~, exact, ranges). package.json also configures ESLint, Prettier, Babel, Jest, Browserslist, and many other tools through their respective configuration keys. The file supports workspaces for monorepo management, bin for CLI tool registration, and files for specifying which files are included when publishing. package.json is the most ubiquitous configuration file in web development — virtually every JavaScript/TypeScript project has one. The npm registry hosts over 2 million packages, all defined by their package.json manifests. The file's central role in the JS ecosystem makes it one of the most important configuration formats in modern software development.