SideEye is a macOS SwiftUI app that lets you keep a sneaky Picture-in-Picture (PiP) preview of your connected monitors. Perfect for presenters, streamers, or anyone who wants to see what’s being shown on an outward-facing screen without constantly turning around.

Features

• Monitor Picker – Choose which connected display you want to mirror.
• Floating Preview Window – Opens a PiP-style window you can resize and keep always-on-top.
• FPS Control – Switch between 30 FPS (smooth) and 10 FPS (power-saving).
• SwiftUI + ScreenCaptureKit – Built for macOS 14+, using Apple’s modern capture APIs.

How It Works

1. Launch SideEye.
2. In the main window, use the drop-down menu to select the monitor you want to mirror.
3. Pick your frame rate:
   • 30 FPS – smoother motion, higher CPU/GPU use
   • 10 FPS – lower motion, more battery friendly
4. Click “Open Floating Preview”.
5. A resizable, floating PiP window will appear showing the chosen monitor.

You can drag, resize, and keep the preview on top of all windows—handy for presentations or live demos.

Requirements

• macOS 14 (Sonoma) or newer
• Screen Recording permission for SideEye enabled in System Settings → Privacy & Security → Screen Recording