package.json Generator: Build a Valid npm Manifest in Your Browser
Create a clean, valid package.json in minutes with the free package.json Generator. Add scripts, dependencies, engines, and exports with live preview and one-click download — no install required.
Free Interactive Tool
package.json Generator
Build a valid package.json with name, version, scripts, dependencies, devDependencies, engines, and metadata fields. Live preview, name and version validation, and one-click download — entirely in your browser.
Table of Contents
Every Node.js project starts with the same file: package.json. It tells npm what your package is called, which version it is, how it should be built, what it depends on, and which Node.js runtime it supports. Get it wrong, and you get broken installs, failed CI pipelines, and cryptic publish errors from the npm registry.
The package.json Generator removes the guesswork. Instead of hand-writing JSON or googling field names, you fill in a simple form — name, version, scripts, dependencies, engines — and watch a valid manifest assemble itself in a live preview. When it looks right, download the finished package.json and drop it straight into your project.
Everything runs in your browser. No account, no install, no upload: your dependency names and project details never leave your machine. It is the fastest way to go from an empty folder to a publish-ready manifest, whether you are starting a library, scaffolding a script, or teaching someone what npm metadata actually means.
Why Use the package.json Generator?
- Zero setup: no npm init wizard, no global tooling, no project scaffolder required — open the page and start building.
- Valid output every time: the version field is checked against semantic versioning (SemVer) syntax, so you cannot save 1.0 or abc as a version by accident.
- Live preview: the JSON updates as you type, so you see exactly which fields will appear in the final file — and which will be omitted when empty.
- Full metadata coverage: name, version, description, keywords, license, module type, entry points (main, types, exports, bin), files, scripts, dependencies, and engines all in one screen.
- Privacy by design: everything is generated client-side in your browser, so private package names and internal tooling details stay on your device.
- Consistent with modern npm: fields like exports and engines follow the current Node.js ecosystem conventions, not decade-old boilerplate.
Key Features
| Feature | What it does |
|---|---|
| Guided form fields | Enter name, version, description, keywords, and license (MIT by default) without remembering JSON syntax |
| Module type selector | Pick commonjs or module (ESM) and the correct type field is emitted |
| Entry point fields | Set main, types, exports, and bin for libraries and CLI tools |
| Scripts editor | Add or remove npm scripts rows — each with a name and a command |
| Dependencies rows | Add packages with name and version, one row at a time |
| Engines field | Declare the minimum Node.js version your package supports |
| Live JSON preview | Watch the manifest update in real time as you fill the form |
| Download button | Export the finished file as package.json ready to commit |
A few details are worth calling out. First, the generator only includes fields you actually filled in — an empty form produces a minimal manifest rather than a wall of nulls, which keeps the output clean. Second, the version input validates against SemVer syntax (for example 1.4.2 or 2.0.0-beta.1), catching typos before they reach a publish step. Third, the reset control clears everything instantly so you can generate several variants back to back.
How to Use
- Open the package.json Generator in your browser.
- Fill in the basics: package name, version (SemVer format), a short description, keywords, and the license — MIT is the default for open source.
- Choose the module type (commonjs or module), then add entry points if you are publishing a library: main, types, exports, or a bin path for CLI tools.
- Add your npm scripts (name plus command, for example build → vite build) and your dependencies (package name plus version range) using the add-row editors.
- Set the engines.node minimum if your code needs a specific runtime, review the live JSON preview, then click Download package.json and commit the file to your project root.
The whole flow takes under two minutes for a typical project — less time than hunting down the correct exports syntax in documentation.
Understanding package.json Fields
A package.json is just JSON, but each field carries specific meaning to npm and Node.js. Knowing what the generator is writing helps you make better choices.
name and version — Together they form the unique identity of a published package on the npm registry. The name must be lowercase and URL-safe; the version must follow SemVer (MAJOR.MINOR.PATCH). The generator validates the version shape so you never publish 1.0 by mistake.
type: module vs commonjs — This single field decides how Node.js interprets your .js files. commonjs (the historical default) uses require() and module.exports; module enables ECMAScript modules with import and export. Setting it explicitly avoids the "Cannot use import statement outside a module" class of errors and lets you rename nothing — modern tooling reads this field first.
main, exports, and types — main is the classic single entry point. exports is the modern replacement: it maps import paths (including subpath imports like my-pkg/utils) and can hide internal files from consumers. types points TypeScript at your declaration file. If you publish a library, prefer exports and keep main as a fallback for older toolchains.
scripts — These are the commands npm run can execute: build, test, dev, prepublishOnly, and any custom name you invent. Well-named scripts are documentation: a new teammate should be able to run npm run and understand the project's workflow at a glance.
dependencies vs devDependencies — Dependencies ship with your package at runtime; devDependencies (build tools, test runners, type checkers) are only needed while developing. The generator's dependency rows record what you declare — keep build tooling out of runtime dependencies so consumers install less.
engines — Declaring engines.node (for example >=20) tells users which runtime your package supports. It prevents the classic bug where your code uses a modern API that older Node.js versions simply do not have.
Practical Use Cases
Starting a new library
You are publishing an npm package for the first time. Fill in the name, set the version to 0.1.0, choose module, add main, types, and exports pointing at your build output, and declare engines.node. Download the file, run npm publish, and the registry accepts it on the first try — no missing-field errors.
Scaffolding internal tools
For scripts and automation that never get published, most fields stay empty — and that is fine. Add just a name, the scripts you need (start, deploy), and your dependencies. The generator emits exactly that minimal manifest, which is cleaner than copying a bloated template from another project.
Teaching and documentation
Writing a tutorial about npm? Screenshots of a finished file are less useful than the process of building one. Walk students through the form: every field they fill maps to a concept — SemVer, ESM vs CommonJS, dependency types — and the live preview shows the JSON materialize in real time.
Standardizing manifests across a team
If each of your repositories has a slightly different package.json layout, generate one canonical file per project type (library, CLI, internal service), commit it as a template, and let teammates regenerate consistent manifests instead of editing JSON by hand.
Best Practices
- Validate the version before every publish: stick to SemVer and bump MAJOR for breaking changes, MINOR for features, PATCH for fixes.
- Set type explicitly: even if you use CommonJS today, stating it avoids surprises when files are added later.
- Prefer exports over main for libraries: it gives you stable public paths and keeps internals private.
- Keep dependencies honest: a package belongs in dependencies only if consumers need it at runtime; move everything else to devDependencies.
- Declare engines.node: it is the cheapest way to prevent "works on my machine" runtime errors.
- Review the live preview before downloading: the preview is the source of truth — if a field you expected is missing, the corresponding form field is empty.
Get a Publish-Ready Manifest in Two Minutes
The package.json Generator turns npm's most fiddled-with file into a two-minute form fill: guided fields, SemVer-validated versions, live preview, and an instant download. No install, no account, no data leaving your browser. Next time you start a project — or clean one up — skip the boilerplate and generate the manifest.
Related Tools You Might Like:
- JSON Formatter — pretty-print, validate, and minify any JSON, including the manifest you just generated.
- NPM Run Scripts Builder — design and organize your npm scripts block before pasting it into a project.
- SemVer Calculator — check how version ranges resolve and plan your next release bump with confidence.
Happy building!
Frequently Asked Questions
Q: Is the package.json Generator free to use? A: Yes. It runs entirely in your browser with no registration, no limits, and no cost — generate as many manifests as you need.
Q: Does my package data get uploaded anywhere? A: No. All generation happens client-side. Your package names, dependencies, and scripts never leave your device.
Q: Can I edit the generated file afterwards? A: Absolutely. The download is a normal package.json — edit it by hand or paste it into the tool's form again to regenerate a clean version.
Q: What is the difference between main and exports? A: main defines one legacy entry point. exports is the modern field that maps multiple entry points, supports subpath imports, and can restrict what consumers can import. Modern libraries typically define both.
Q: Which module type should I choose, module or commonjs? A: Choose module for new projects using import/export syntax with modern tooling. Choose commonjs if your code relies on require() or you need compatibility with older Node.js environments.