The Unity Package Manager is the official package management system for Unity. It does the following:
You can use the Package Manager to define project dependencies, resolve package dependencies, download and add packages as needed, and integrate content in your projects.
For general information on what a package is and how the Unity Package Manager works, see the Packages documentation.
Packages can contain the following:
Each package also contains a Package manifest file that includes information such as the package name, its version, a list of its dependencies, and the URL to its repository.
To create a new package:
Create an empty shell for the package using one of these methods:
Implement your tools, libraries, and any assets your package requires.
Make sure the layout of your package follows the package layout convention for Unity packages.
Add tests to your package. Tests are essential for ensuring that the package works as expected in different scenarios:
Tests/Editor.Tests/Runtime.Rename and update the assembly definition files.
You can update the CHANGELOG.md file every time you publish a new version. Every new feature or bug fix should have a trace in this file. For more details on the chosen changelog format, see the Keep a Changelog documentation.
This is optional for packages that you don’t share, but strongly recommended for shared packages, so that users know which version best suits their needs.
You can include licenses and third-party notices in the LICENSE.md and THIRD PARTY NOTICES.md files.
This is optional for packages that you don’t share, but strongly recommended for shared packages, so that your users don’t misuse your packages or violate any third-party licenses.
Share your package.
Follow these instructions if you want to create a custom package inside your project folder.
Open the Unity Hub, and create an empty project on your computer.
You can also use an existing project on your computer, and embed the package under your project or install the package from a local folder. However, starting with a new project makes the package contents less prone to errors.
Using your computer’s file manager (for example the Windows File Explorer or the macOS Finder), navigate to your project folder and locate the Packages subfolder.
Create a new subfolder for your package inside the Packages folder using a name that matches the package name. For example, if your package is called com.example.mypackage, the subfolder should also be called com.example.mypackage.
Note: This is particularly important if your package contains assets, because the AssetDatabase looks for an asset path that matches Packages/<your-package-name>/Assets, regardless of what the actual folder is called.
Open your preferred text editor and create a JSON file called package.json.
Save it under the new package root folder you created.
Fill out all required and mandatory fields in the package manifest (package.json) file.
When you reopen Unity, the new package appears in the Package Manager window and in the Project window, where you can view and modify the package contents. If you select the package.json file in the Project window, you can also modify its contents directly in the Inspector window.
Follow these instructions if you want to create a custom package outside your project folder:
Using your computer’s file manager (for example the Windows File Explorer or the macOS Finder), create a folder for your package.
You can also use an existing location if you’ve already created some content for your package.
Make sure the layout of your folder structure follows the package layout convention for Unity packages. For example, if you have Editor and Runtime libraries, make sure they are stored under the Editor and Runtime folders.
Open your preferred text editor and create a JSON file called package.json.
Save it under the package root folder.
Fill out all required and mandatory fields in the package manifest (package.json) file.
In Unity, create a new project or open an existing project.
Open the Packages window and follow the instructions for installing a local package, using the package.json file you just created.
The new package appears in the Package Manager window and in the Project window, where you can view and modify the package contents. If you select the package.json file in the Project window, you can also modify its contents directly in the Inspector window.