Packages have become more and more essential to Unity game development with each new release. OpenUPM is an open source package repository and command line interface that makes it quick and easy to add packages directly to your Unity project.
One obvious question you may have is… Why not just use the Unity Package Manager? Well… they answer that:
Unity Asset Store is the official solution for publishing software, assets, and services, offering both paid and free content. However, assets are installed into the Asset folder. The old fashion way is good for managing assets, but it lacks dependency management for libraries. Unity has a progressive way to encourage its large content to convert to the UPM format. But it takes time.
Unlike the Unity asset store, OpenUPM is focusing on the open-source from day one, and our open-source community is growing fast. Both the Unity Asset Store and OpenUPM will continue growing and inspiring each other.
npm install -g openupm-cli
Once installed, you run the command openupm to search for and install Unity packages. You can see how to use openupm from the command line in the video below, including finding packages, adding to your project, verifying they are installed and uninstalling openupm. There are hundreds of open source packages in the OpenUPM repository which you can browse and search through here. In sticking with the open source theme, OpenUPM is also open source under the BSD3 license with the source code available on GitHub.