SpinWin is an open-source macOS menubar app that visually rotates any application window by arbitrary angles or continuous spin. Created by developer alokdhir after finding no existing solution, it works around macOS's lack of public window-rotation APIs.

The app hides the target window off-screen via the Accessibility API (where it continues rendering), captures its buffer continuously with ScreenCaptureKit, and displays the frames in a transparent, borderless overlay window rotated via a CALayer transform. This approach avoids private SkyLight calls and SIP disabling.

Written in Swift under the MIT license, SpinWin is signed and notarized for Gatekeeper-free launches. Users grant Screen Recording and Accessibility permissions, then left-click the menubar icon to select a rotation mode and target window. The overlay can be dragged and rotated freely; pressing Esc restores the original window.

Current limitations include non-interactive overlays (clicks don't pass through), Mission Control exposing the hidden window, and potential rendering throttling for off-screen windows. The project is available on GitHub at alokdhir/spinwin with 11 points and 2 comments on Hacker News.