Press Release: Cirrus Labs Successfully Enforces Its Fair Source License¶
New York City, NY – October 27th, 2025 – Cirrus Labs, Inc., a leading provider of platforms for digital transformation, today announced that it has reached a settlement agreement regarding a violation of its Fair Source License.
Cirrus Labs makes its Tart Virtualization Toolset, a leading virtualization toolset to build, run and manage macOS and Linux virtual machines (VMs) on Apple Silicon, freely available on GitHub under the Fair Source License, a source-available license. Tart is used by tens of thousands of engineers at no charge within its generous free‑use limits. Many large enterprises that need to exceed those limits support continued development through paid licenses. Cirrus Labs also uses Tart to power Cirrus Runners — a drop‑in replacement for macOS and Linux runners for GitHub Actions — offered at a fixed monthly price for unlimited usage.
Cirrus Labs discovered that, despite a prior licensing request that was declined due to a conflict of interest, another company used Tart in a manner that exceeded the license’s free‑use limits, in order to create a competing product.
After several months of negotiations, the matter was settled and a settlement payment to Cirrus Labs was agreed upon.
Comment by Fedor Korotkov, CEO of Cirrus Labs
As a company we embrace healthy competition that ultimately benefits the end user. Most of our users have no trouble complying with our license, and even when they need something more than our free use limits, we can almost always grant them a license that fits their needs. This was an exceptional case. We are pleased to have reached this settlement, which validates our source-available licensing strategy and reinforces our commitment to protecting our company and serving our community.
Cirrus Labs was represented in this matter by Jordan Raphael of Byron Raphael LLP, a boutique intellectual property law firm, and Heather Meeker, a well-known specialist in open source and source available licensing.
The specific financial terms of the settlement and the identity of the counterparty remain confidential.
About Cirrus Labs: Cirrus Labs, Inc. is a bootstrapped developer-infrastructure company founded in 2017. Our offerings among others include Tart and Cirrus Runners, and our software is used by teams at category-leading companies including Atlassian, Figma, Zendesk, Sentry and many more.
Learn more at https://tart.run/ and https://cirrus-runners.app/.
Contact: hello@cirruslabs.org