A command line utility that synchronizes asset files from npm packages into an appropriate directory of a game project that is made using the Unity game engine. Please read through the readme before using.
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A command line utility that synchronizes asset files from yarn / npm packages into an appropriate directory of a game project that is made using the Unity game engine.


The package can be executed using the npx tool that ships with Node.js.

Use the following command at the root of your project to synchronize the Unity packages into your project's "Assets" directory:

$ npx unity3d-package-syncer

For example, if you were to add a new package with yarn:

yarn add unity3d-package-example
npx unity3d-package-syncer

Or, with npm:

npm install --save unity3d-package-example
npx unity3d-package-syncer

If your package has an editor script that needs to generate data assets (such as presets, project settings, etc) then it should store those in the Assets/Plugins/PackageData/{package-name} path. You may find the unity3d-package-utils package useful in assiting with this.

yarn vs npm

From my experience the yarn tool seems to work better with the Unity development workflow since packages are installed deterministically. The minimum required version of yarn is v1.9.0.

Creating Unity packages

The unity3d-package-syncer only considers packages that have the keyword unity3d-package declared in their package.json file when checking and copying files from the package into a Unity project.

The following is an example of how the package.json of such a package might look:

  "name": "some-cool-package",
  "version": "1.0.0",
  "description": "A cool package for Unity projects which ...",
  "keywords": [

For an example checkout the unity3d-package-example repository.

Which files are copied from the package?

All files in the package's assets/ directory are copied into the root of the package inside the Unity project.

Some extra files are also copied from the package into the Unity project:

  • package.json (required)


  • README.md

For example, the file structure of the following package:

  |-- assets/
  |    |-- Logo.png
  |    |-- Logo.png.meta
  |-- docs/
  |    |-- getting-started.md
  |-- index.js
  |-- package.json
  |-- README.md

Results in the following directory structure in a Unity project:

  |-- Assets/
  |    |-- Plugins/
  |    |    |-- Packages/
  |    |    |    |-- some-cool-package/
  |    |    |    |    |-- Logo.png
  |    |    |    |    |-- Logo.png.meta       (Copied from package)
  |    |    |    |    |-- LICENSE
  |    |    |    |    |-- LICENSE.meta        (Unity generates this automatically)
  |    |    |    |    |-- package.json
  |    |    |    |    |-- package.json.meta   (Unity generates this automatically)
  |    |    |    |    |-- README.md
  |    |    |    |    |-- README.md.meta      (Unity generates this automatically)
  |    |    |    |-- some-cool-package.meta   (Unity generates this automatically)
  |-- Library/
  |-- package.json

The *.meta files that are automatically generated by Unity should be included for each file that is included in the assets/ directory of your package.

Since nothing in the Unity project should be referencing the extra files; there shouldn't be any issues with these being automatically generated by Unity each time the package is copied into your project.

How does the unity3d-package-syncer know when a package needs to be copied?

  • If the package has not yet been copied into the Unity project.

  • If the version of the package already in the Unity project differs from the version of the currently installed package.

How does the unity3d-package-syncer know when a package needs to be removed?

  • If the package exists in the Unity project but is not declared in package.json.

What happens if I modify the package files that were copied into the Unity project?

IMPORTANT: Any modifications will be lost when the package is next updated or uninstalled.

If you need to modify the files of the package then you will need to update the package with the modifications and adjust the version number of the package.

If you want to modify the files of a package that you don't currently maintain, then you will need to create a fork of the original package so that you can maintain that.

Packages with editor scripts that create asset files SHOULD NOT be storing these inside the {unity-project}/Assets/Plugins/Packages/ directory structure because these files will be lost if the package is updated or uninstalled.

If your package needs to generate configuration and/or data files then they should be stored in a different location in the Unity project. I would suggest that packages adopt the following directory structure for generated data files for consistency with one another:


Contribution Agreement

This project is licensed under the MIT license (see LICENSE). To be in the best position to enforce these licenses the copyright status of this project needs to be as simple as possible. To achieve this the following terms and conditions must be met:

  • All contributed content (including but not limited to source code, text, image, videos, bug reports, suggestions, ideas, etc.) must be the contributors own work.

  • The contributor disclaims all copyright and accepts that their contributed content will be released to the public domain.

  • The act of submitting a contribution indicates that the contributor agrees with this agreement. This includes (but is not limited to) pull requests, issues, tickets, e-mails, newsgroups, blogs, forums, etc.