Facebook today is open-sourcing Yarn, a package manager for efficiently installing JavaScript packages that represent dependencies for applications. Yarn is available now on GitHub under a BSD-2-Clause license.

Facebook used the Npm client for years but ultimately chose to build its own system to deal with security and performance concerns. Facebook says the system works about 10 times faster than Npm for some of its software projects. And that’s significant, given the popularity of Npm, which is supported by startup Npm Inc. To demonstrate Yarn’s performance gains, Facebook is posting benchmark results online today.

“At Facebook, we’re already using Yarn in production, and it’s been working really well for us,” Facebook software engineers James Kyle, Sebastian McKenzie, and Christoph Pojer wrote in a blog post. “It powers the dependency and package management for many of our JavaScript projects. With each migration we’ve enabled engineers to build offline and helped speed up their workflow.”

Like other web companies, Facebook often open-sources code. But a package manager is lower down than usual — it’s a tool that makes it easy to work with many other tools. And while there are other JavaScript (and specifically Node.js-centric) package managers around today, there aren’t many. The performance gains alone may be enough to help Yarn gain considerable adoption over time.

Check out Kyle, McKenzie, and Pojer’s full blog post for much more on Yarn’s history, architecture, and installation process.