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Package JSON Scaffold Generator

Generate package.json scaffolds from project metadata and script presets.

About Package JSON Scaffold Generator

Package.json Scaffold Generator on UtilityKit creates a complete, well-structured `package.json` for new Node.js projects in seconds. Enter your project name, version, description, and license, then select from common script templates (start, dev, test, build, lint, format), configure your Node.js engine range, and pick from a curated devDependency list — TypeScript, ESLint, Prettier, Jest, Vitest, nodemon, tsx, and more. The generator assembles a standards-compliant JSON file with the correct field ordering (name, version, description, main, scripts, engines, devDependencies) that passes `npm install` validation without modification. No more trailing commas or mistyped field names in a blank file. Ideal for bootstrapping prototypes, monorepo packages, shared libraries, and CLI tools with a consistent, team-aligned baseline.

Why use Package JSON Scaffold Generator

Correct Field Ordering

Follows the npm-recommended field order (name → version → description → main → scripts → engines → dependencies → devDependencies), keeping diffs clean and readable.

Scripts That Actually Work

Pre-filled script values use real, runnable commands rather than placeholder strings, so `npm run dev` or `npm test` works immediately after install.

Engine Range Enforcement

Setting the `engines` field warns developers and CI systems when they try to install on an unsupported Node version, preventing cryptic runtime failures.

Curated DevDependency List

Only widely adopted, actively maintained packages are offered. No obscure or deprecated tooling — every listed package has millions of weekly downloads.

JSON Syntax Guaranteed

The generator outputs valid JSON every time, eliminating trailing comma errors, unclosed braces, and unquoted keys that `npm install` rejects silently.

Team Baseline Consistency

Generating from a shared template ensures all packages in a monorepo or team start with the same script names, engine constraints, and tooling versions.

How to use Package JSON Scaffold Generator

  1. Enter your package name in kebab-case (e.g. `my-api-service`), semantic version (default `0.1.0`), a short description, and your name or organisation as the author.
  2. Choose a license from the dropdown: MIT, ISC, Apache-2.0, GPL-3.0, or UNLICENSED for private packages.
  3. Select the npm scripts you need: `start`, `dev` (with nodemon), `test`, `build`, `lint` (ESLint), and `format` (Prettier). Each script inserts the correct default command.
  4. Set the `engines` Node.js version range (e.g. `>=20.0.0`) to signal minimum runtime requirements to npm and deployment platforms.
  5. Tick the devDependencies you want pre-listed: TypeScript, ESLint, Prettier, Jest, Vitest, nodemon, tsx, `@types/node`, or husky.
  6. Click Generate, then copy or download the `package.json`. Save it to your project root and run `npm install` to pull the listed devDependencies.

When to use Package JSON Scaffold Generator

  • When bootstrapping a new Node.js microservice, CLI tool, or library and you want a valid `package.json` without copying from a previous project.
  • When starting a new monorepo workspace package that needs a consistent script and engine baseline matching your other packages.
  • When teaching Node.js fundamentals and you want to show learners a well-structured `package.json` with every common field explained.
  • When converting a plain JavaScript project to TypeScript and need to add the correct TypeScript, `@types/node`, and `tsc` build script configuration.
  • When you want to enforce a minimum Node.js engine version across your team's projects and need the correct `engines` field syntax.
  • When quickly prototyping an npm package and you need a publishable `package.json` with the name, version, main, and license fields correctly set.

Examples

Basic Node.js REST API

Input: Name: my-rest-api, Version: 0.1.0, License: MIT, Scripts: start/dev/test, Engine: >=20, DevDeps: nodemon, jest

Output: { "name": "my-rest-api", "version": "0.1.0", "description": "", "main": "index.js", "scripts": { "start": "node index.js", "dev": "nodemon index.js", "test": "jest" }, "engines": { "node": ">=20.0.0" }, "license": "MIT", "devDependencies": { "jest": "^29.0.0", "nodemon": "^3.0.0" } }

TypeScript ESM library

Input: Name: my-lib, Version: 1.0.0, Type: module, License: MIT, Scripts: build/test, Engine: >=18, DevDeps: typescript, @types/node, vitest

Output: { "name": "my-lib", "version": "1.0.0", "type": "module", "main": "dist/index.js", "scripts": { "build": "tsc", "test": "vitest run" }, "engines": { "node": ">=18.0.0" }, "license": "MIT", "devDependencies": { "@types/node": "^20.0.0", "typescript": "^5.0.0", "vitest": "^1.0.0" } }

Private monorepo workspace package

Input: Name: @myorg/shared-utils, Private: true, Version: 0.0.1, Scripts: build/lint/format, DevDeps: typescript, eslint, prettier

Output: { "name": "@myorg/shared-utils", "version": "0.0.1", "private": true, "scripts": { "build": "tsc", "lint": "eslint src", "format": "prettier --write src" }, "license": "UNLICENSED", "devDependencies": { "eslint": "^9.0.0", "prettier": "^3.0.0", "typescript": "^5.0.0" } }

Tips

  • Add `"private": true` to your `package.json` if the package is not intended for npm publishing. This prevents accidental `npm publish` and suppresses irrelevant npm audit warnings about missing public registry fields.
  • Use `npm pkg set scripts.prepare="husky"` after generating to wire up git hooks automatically on install — pair with the `husky` devDependency to enforce lint-staged checks on every commit.
  • Set `"sideEffects": false` in library packages to enable tree-shaking in bundlers like Webpack and Rollup, reducing consumer bundle sizes.
  • List `node` and `npm` version ranges separately in `engines` (e.g. `"node": ">=20"`, `"npm": ">=10"`) to catch version mismatches in both the runtime and the package manager.
  • Run `npm pkg fix` after pasting the generated file into your project — it validates and normalises fields like `name` (converts to lowercase kebab-case if needed).

Frequently Asked Questions

Does the generator add exact version numbers to devDependencies?▾
It inserts the current stable major version with a caret prefix (e.g. `"eslint": "^9.0.0"`) to allow compatible minor and patch updates while keeping your project on the major version you selected. Run `npm install` to resolve and lock exact versions in `package-lock.json`.
What is the difference between `dependencies` and `devDependencies`?▾
`dependencies` are packages your application needs at runtime (e.g. Express, Zod). `devDependencies` are packages only needed during development and build (e.g. TypeScript, ESLint, Jest). When you run `npm install --production`, only `dependencies` are installed — important for keeping Docker images lean.
What does the `engines` field actually do?▾
It declares the Node.js (and npm) versions your package is tested and supported on. npm warns (but does not block) installation when the running Node version does not satisfy the range. Some CI systems and deployment platforms enforce it as an error with `--engine-strict`.
Should I use `npm`, `yarn`, or `pnpm` scripts?▾
The generated scripts use plain Node and locally installed binaries (via `npx` or direct path in `node_modules/.bin`), so they work identically with npm, yarn, and pnpm. Choose whichever package manager your team standardises on.
What is the `main` field for?▾
`main` specifies the entry point file that Node.js loads when your package is `require()`-d by another package. For applications (not libraries), it is less critical, but setting it to `index.js` or your server entry is good practice.
Can I add a `type: module` field for ESM?▾
Yes — toggle the ESM option to add `"type": "module"` to the generated file, which tells Node.js to treat `.js` files as ES modules using `import`/`export` syntax. Be aware this changes how you use `require()` and affects some tooling compatibility.
What is `packageManager` and should I set it?▾
`packageManager` (e.g. `"packageManager": "pnpm@9.0.0"`) is a Corepack field that pins the package manager version for the project. It is optional but recommended in monorepos to prevent team members from accidentally using a different package manager version.
How do I publish the generated package to npm?▾
After customising the generated `package.json`, run `npm login` and then `npm publish`. Ensure `name` is unique on the npm registry, `version` follows semver, and you have included a `files` array or `.npmignore` to control what gets published.

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Glossary

Semantic versioning (semver)
A versioning scheme with MAJOR.MINOR.PATCH numbers. Breaking changes increment MAJOR, new backwards-compatible features increment MINOR, bug fixes increment PATCH. npm uses semver ranges in dependency fields.
devDependencies
npm packages required only during development and build (linters, test runners, compilers). They are excluded from production installs and should not be needed at runtime.
engines field
A `package.json` field declaring the Node.js and npm versions the package is supported on. npm warns on version mismatch; `--engine-strict` makes it an error.
Caret range (^)
An npm version range prefix (e.g. `^9.0.0`) that allows updates to any compatible minor and patch version within the same major, helping projects receive bug fixes without breaking changes.
ESM (ES Modules)
The ECMAScript standard module system using `import`/`export` syntax. Enabled in Node.js by setting `"type": "module"` in `package.json`, replacing the older CommonJS `require()` system.
Lifecycle script
A special npm script name (e.g. `prepare`, `postinstall`, `pretest`) that npm automatically runs at defined points in the package install and publish lifecycle without being explicitly called.