Stackline

A Swift application that interfaces with Yabai to display interactive stack indicators for stacked windows on macOS.

Installation

Prerequisites

• macOS 15.0 or later
• Yabai installed and running

Installing the pre-built binary

1. Download the DMG from the releases
2. Mount the DMG by double clicking
3. Drag the app from the DMG to the Applications folder
4. Run the application

The application is signed, notarized and stapled, so you should be able to just run from there!

Building from Source

Note: I recently swapped from using plain old swift to xcode to build a signed app bundle

Prerequisites

• Xcode 26+ (for the app icon)
  • It will compile with a lower version, but your mileage may vary

Steps

1. Clone the repository:

   git clone https://github.com/liam-mackie/stackline-swift.git
   cd stackline-swift

2. Build the application:

   xcodebuild -scheme Stackline -configuration Release -derivedDataPath build

3. The built app will be located at:

   build/Build/Products/Release/Stackline.app

4. Copy it to your applications folder:

   cp -r build/Build/Products/Release/Stackline.app /Applications

Configuration

Yabai Setup

Stackline automatically sets up Yabai signals for you! When you start Stackline, it will:

1. Remove any old Stackline signals (identified by stackline-*)
2. Add new signals with the correct path to your current Stackline binary

Stackline automatically removes its signals when terminating normally.

Auto-start

To start Stackline automatically, run stackline, then open preferences from the menu bar icon. In the general, enable "Launch at Login"

Usage

Interacting with Stacks

You can click on a stacked application's icon, pill or dot to swap to the application.

Command Line Interface

Stackline supports several command-line options:

# Start the application
/Applications/Stackline.app/Contents/MacOS/Stackline

# Handle a signal from Yabai (used internally by automatic signal setup)
/Applications/Stackline.app/Contents/MacOS/Stackline handle-signal window_focused $YABAI_WINDOW_ID

# Show version information
/Applications/Stackline.app/Contents/MacOS/Stackline --version

# Show help
/Applications/Stackline.app/Contents/MacOS/Stackline --help

Development

Contributing

Contributions are welcome! Please:

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Add tests if applicable (I probably haven't)
5. Submit a pull request

Requirements

• macOS: 15.0+ (tested on macOS 26).
• Yabai: Any recent version
• Architecture: Intel x86_64 or Apple Silicon (Tested on Apple Silicon)

Acknowledgments

• Stackline by @AdamWagner - this was one of the main reasons I wanted to make this
• Yabai by @koekeishiya - Yabai is essential to my workflow, as well as many others around the world
• Apple's SwiftUI framework for making this a relatively simple step into making a UI based app