package.json Generator

What Is package.json

package.json is the manifest file for Node.js projects and npm (Node Package Manager) packages. It defines the project's name, version, dependencies, scripts, entry points, and metadata. Every Node.js project — from simple scripts to complex web applications — starts with a package.json file.

This tool generates properly structured package.json files with common configurations for various project types, saving setup time and ensuring best practices are followed from the start.

Key Fields

Field	Required	Purpose	Example
name	Yes	Package identifier (lowercase, no spaces)	"my-api-server"
version	Yes	Semantic version	"1.0.0"
description	No	Brief package description	"REST API for user management"
main	No	Entry point for CommonJS	"dist/index.js"
module	No	Entry point for ES modules	"dist/index.mjs"
scripts	No	Named command shortcuts	{"start": "node server.js"}
dependencies	No	Production packages	{"express": "^4.18.0"}
devDependencies	No	Development-only packages	{"jest": "^29.0.0"}
engines	No	Required Node.js/npm versions	{"node": ">=20.0.0"}
license	No	License identifier	"MIT"
type	No	Module system ("module" or "commonjs")	"module"

Common Use Cases

• New project scaffolding: Generate a complete package.json with appropriate scripts, dependencies, and configuration for your project type (API, CLI, library, web app)
• Library publishing: Create package.json with correct fields for publishing to npm, including exports, files, keywords, and repository metadata
• Monorepo workspace setup: Generate root and workspace package.json files for monorepo tools like npm workspaces, Turborepo, or Lerna
• Migration projects: Convert existing projects to new module systems (CommonJS to ESM) with correct type and exports fields
• CI/CD configuration: Define scripts for testing, building, linting, and deployment that CI/CD pipelines will execute

Best Practices

1. Pin exact dependency versions for applications — Use exact versions (no ^ or ~) in application projects to ensure reproducible builds. Use lock files (package-lock.json) and commit them.
2. Use ranges for library dependencies — Libraries should use ^ ranges to allow consumers to resolve compatible versions without conflicts.
3. Define an engines field — Specify the minimum Node.js version your project requires. This prevents cryptic runtime errors when users run your code on unsupported versions.
4. Keep scripts organized — Define standard scripts: start, build, test, lint, dev. Use pre/post hooks (pretest, postbuild) for ordered workflow steps.
5. Set "type": "module" for new projects — ES modules are the standard. New projects should default to ESM unless they need CommonJS compatibility.
6. Use the files field for packages — When publishing to npm, use the files array to specify exactly which files to include. This keeps your package small and avoids leaking unintended files.