Select a framework preset (React, Next.js, Express, library, or CLI tool) to populate common dependencies, scripts, and configuration fields. Then customize the package name, version, description, entry points (main, module, types for libraries), and scripts. The dependency editor lets you add, remove, and set version ranges for both dependencies and devDependencies. Common scripts like dev, build, test, and lint are pre-configured based on your chosen preset. The generator also handles metadata fields like license, repository, author, keywords, and engines for Node.js version requirements. The output is a valid package.json file ready to download or copy.

Dependencies are packages required at runtime when your application or library runs in production. Examples include React, Express, lodash, and database drivers. devDependencies are packages only needed during development, testing, and building. Examples include TypeScript, ESLint, Prettier, Jest, and build tools like Vite or webpack. When someone installs your published npm package, only dependencies are installed, not devDependencies. Running npm install in a project installs both. Running npm install --production or setting NODE_ENV=production skips devDependencies. Placing packages in the correct category reduces production bundle size and install time. If in doubt, ask: does the running application import this package directly?

Modern packages use the exports field to define public entry points with conditional resolution. The main field points to the CommonJS entry (dist/index.cjs), module points to the ESM entry (dist/index.mjs), and types points to TypeScript declarations (dist/index.d.ts). The exports field provides finer control: set "." for the main entry, "./utils" for subpath exports, and use conditions like import, require, and types for format-specific resolution. Setting "type": "module" makes .js files treated as ESM by default. For TypeScript libraries, include a types condition in exports so consumers get type definitions automatically. The generator configures these fields correctly based on your selected output format.