AltTab — Windows-Style Alt-Tab Window Switcher for macOS

Introduction

AltTab is a macOS utility that replaces the default Cmd+Tab app switcher with a Windows-style window switcher. It shows thumbnail previews of every open window, not just applications, letting you switch to a specific window directly. It is written in Swift and runs as a lightweight menu bar app.

What AltTab Does

• Shows thumbnail previews of all open windows when triggered by a keyboard shortcut
• Switches between individual windows rather than just applications
• Supports multiple keyboard shortcuts for different switching behaviors
• Displays windows from all Spaces and can filter by the current Space
• Hides or minimizes windows directly from the switcher overlay

Architecture Overview

AltTab is a native Swift application that uses the macOS Accessibility API and CGWindowList to enumerate and capture window thumbnails. When the hotkey is pressed, it captures screenshots of all visible windows, renders them in a grid overlay, and handles navigation via keyboard or mouse. It runs as a background agent app with a menu bar icon for configuration.

Self-Hosting & Configuration

• Install via Homebrew Cask or download the .dmg from the project website
• Grant Accessibility permissions in System Settings for window enumeration to work
• Customize the trigger shortcut, thumbnail size, and number of rows in Preferences
• Filter which apps appear in the switcher using the blacklist feature
• Set appearance options including theme, window title display, and animation speed

Key Features

• Window-level switching: switch to specific windows, not just apps
• Thumbnail previews: see live previews of each window before switching
• Customizable shortcuts: configure multiple hotkeys for different behaviors
• Spaces support: show windows from all Spaces or the current one only
• Blacklist: exclude specific apps from appearing in the switcher

Comparison with Similar Tools

• macOS Cmd+Tab: built-in but only switches between apps, not windows
• Witch: similar window-switching concept but paid; AltTab is free and open source
• Contexts: powerful window switcher with search; AltTab is simpler and lighter
• rcmd: app-switching by app name; AltTab focuses on visual window thumbnails

FAQ

Q: Why does AltTab need Accessibility permissions? A: macOS requires Accessibility access for apps to enumerate windows and capture thumbnails from other applications.

Q: Does it work with full-screen apps and Spaces? A: Yes. AltTab can show windows from all Spaces and handles full-screen apps.

Q: Can I use Cmd+Tab instead of Option+Tab? A: Yes. You can remap the shortcut to any key combination in the Preferences panel.

Q: Is AltTab free? A: Yes, it is completely free and open source under the GPL-3.0 license.

Sources

• Repository: https://github.com/lwouis/alt-tab-macos
• Website: https://alt-tab-macos.netlify.app