Tart

Tart is an open-source virtualization toolset designed to build, run, and manage macOS and Linux virtual machines (VMs) on Apple Silicon. It leverages Apple's native Virtualization.Framework to deliver near-native performance, making it ideal for CI pipelines and automation workflows. Tart supports OCI-compatible container registries for pushing and pulling VM images, and integrates seamlessly with any CI system. It powers Cirrus Runners, a drop-in replacement for GitHub-hosted runners offering 2–3× better performance.

• Near-native performance — Uses Apple's Virtualization.Framework for benchmark-proven performance close to bare metal.
• OCI registry support — Push and pull virtual machine images from any OCI-compatible container registry, just like Docker images.
• Packer Plugin — Automate VM creation using the Tart Packer Plugin for repeatable, infrastructure-as-code VM builds.
• CI system integration — Easily integrates with GitHub Actions, Cirrus CI, and any other CI/CD platform.
• Homebrew installation — Get started instantly with brew install cirruslabs/cli/tart on any Apple Silicon Mac running macOS 13 Ventura or later.
• macOS and Linux support — Run both macOS and Linux VMs side by side on the same Apple Silicon host.
• Cirrus Runners powered — Tart is the engine behind Cirrus Runners, a managed service offering fast, cost-effective GitHub Actions runners.
• Fair Source licensed — The project is available on GitHub and free to use for most purposes under its Fair Source license.

Note: Acquired by OpenAI in April 2026.