Package.json Generator Free Online Tool 2026

Last updated March 22, 2026

Basic Node.js Application package.json

A minimal package.json for a Node.js web application:

{
  "name": "my-web-app",
  "version": "1.0.0",
  "description": "A Node.js web application",
  "main": "src/index.js",
  "scripts": {
    "start": "node src/index.js",
    "dev": "nodemon src/index.js",
    "test": "jest"
  },
  "engines": {
    "node": ">=18.0.0",
    "npm": ">=9.0.0"
  },
  "author": "Jane Doe <jane@example.com>",
  "license": "MIT",
  "dependencies": {
    "express": "^4.18.2"
  },
  "devDependencies": {
    "nodemon": "^3.0.1",
    "jest": "^29.7.0"
  }
}

TypeScript Library package.json

A package intended to be published to npm with TypeScript support:

{
  "name": "my-utility-lib",
  "version": "1.0.0",
  "description": "A utility library with TypeScript support",
  "main": "./dist/index.cjs",
  "module": "./dist/index.js",
  "types": "./dist/index.d.ts",
  "exports": {
    ".": {
      "import": "./dist/index.js",
      "require": "./dist/index.cjs",
      "types": "./dist/index.d.ts"
    }
  },
  "files": [
    "dist",
    "README.md",
    "LICENSE"
  ],
  "scripts": {
    "build": "tsup src/index.ts --format cjs,esm --dts",
    "test": "vitest run",
    "lint": "eslint src --ext .ts",
    "prepublishOnly": "npm run build && npm test"
  },
  "keywords": ["utility", "typescript"],
  "license": "MIT",
  "devDependencies": {
    "typescript": "^5.3.3",
    "tsup": "^8.0.1",
    "vitest": "^1.2.0",
    "eslint": "^8.56.0"
  }
}

Version Range Strategies

Understanding the three main version range operators:

{
  "dependencies": {
    // Caret (^) — allows minor and patch updates
    // ^1.2.3 accepts >=1.2.3 <2.0.0
    "express": "^4.18.2",

    // Tilde (~) — allows only patch updates
    // ~1.2.3 accepts >=1.2.3 <1.3.0
    "lodash": "~4.17.21",

    // Exact — locks to specific version
    "critical-dep": "2.0.1",

    // Latest — always installs newest (avoid in production)
    "dev-tool": "*"
  }
}

Use ^ for most dependencies (safe updates), ~ for dependencies where minor changes might break things, and exact versions for security-critical packages.

Modern ESM + CJS Dual Package

Supporting both ES modules and CommonJS with the exports field:

{
  "name": "my-package",
  "version": "1.0.0",
  "type": "module",
  "exports": {
    ".": {
      "import": {
        "types": "./dist/esm/index.d.ts",
        "default": "./dist/esm/index.js"
      },
      "require": {
        "types": "./dist/cjs/index.d.cts",
        "default": "./dist/cjs/index.cjs"
      }
    },
    "./utils": {
      "import": "./dist/esm/utils.js",
      "require": "./dist/cjs/utils.cjs"
    }
  },
  "main": "./dist/cjs/index.cjs",
  "module": "./dist/esm/index.js",
  "types": "./dist/esm/index.d.ts"
}

React Application package.json

A Vite-based React TypeScript application:

{
  "name": "my-react-app",
  "version": "0.1.0",
  "private": true,
  "scripts": {
    "dev": "vite",
    "build": "tsc && vite build",
    "preview": "vite preview",
    "test": "vitest run",
    "lint": "eslint src --ext .ts,.tsx --max-warnings 0",
    "format": "prettier --write src/**/*.{ts,tsx}"
  },
  "dependencies": {
    "react": "^18.2.0",
    "react-dom": "^18.2.0"
  },
  "devDependencies": {
    "@types/react": "^18.2.55",
    "@types/react-dom": "^18.2.19",
    "@vitejs/plugin-react": "^4.2.1",
    "typescript": "^5.3.3",
    "vite": "^5.1.0",
    "vitest": "^1.2.0",
    "eslint": "^8.56.0",
    "prettier": "^3.2.4"
  }
}

Repository and Publishing Fields

Fields that appear on the npm package page:

{
  "name": "my-package",
  "version": "1.0.0",
  "description": "A helpful utility package",
  "keywords": ["utility", "helper", "tools"],
  "author": {
    "name": "Jane Doe",
    "email": "jane@example.com",
    "url": "https://janedoe.example.com"
  },
  "contributors": [
    "John Smith <john@example.com>"
  ],
  "license": "MIT",
  "repository": {
    "type": "git",
    "url": "https://github.com/example/my-package.git"
  },
  "bugs": {
    "url": "https://github.com/example/my-package/issues",
    "email": "bugs@example.com"
  },
  "homepage": "https://my-package.example.com",
  "funding": {
    "type": "github",
    "url": "https://github.com/sponsors/example"
  }
}

Files Field — Controlling npm Publish Content

Specify exactly what gets published to npm:

{
  "files": [
    "dist",          // Built output
    "src",           // Source (optional, for source maps)
    "README.md",
    "LICENSE",
    "CHANGELOG.md"
  ]
  // Automatically excluded (even without .npmignore):
  // node_modules, .git, test files, .env files
}

The files whitelist approach is safer than .npmignore — you explicitly choose what to include rather than trying to exclude everything you don't want.

Peer Dependencies

For plugins and packages that require a host package:

{
  "name": "react-my-component",
  "peerDependencies": {
    "react": "^17.0.0 || ^18.0.0",
    "react-dom": "^17.0.0 || ^18.0.0"
  },
  "peerDependenciesMeta": {
    "react-dom": {
      "optional": true
    }
  },
  "devDependencies": {
    "react": "^18.2.0",
    "react-dom": "^18.2.0"
  }
}

Peer dependencies tell npm that the consuming project must have these packages installed. They are not installed automatically — the user is responsible for providing them.