DockDoor

About

DockDoor adds window previews to the Mac Dock. Point at any app's icon and you can see all of its open windows, much like the taskbar on Windows. It also adds Alt+Tab window switching, which lets you pick a specific window rather than just an app, along with keyboard controls and snap and gesture support. The app is free and open source, runs on macOS 13 Ventura and later on both Apple silicon and Intel, and can be installed with Homebrew.

From the preview you can close, minimize, or quit windows without leaving the app you're in, and windows on other Spaces and displays, including minimized and hidden ones, also appear. Previews can be shown as thumbnails, a compact title list, or large previews, and the app includes optional extras such as folder popups, music controls, and gesture-based window snapping. The website states that nothing leaves your Mac: there are no servers, analytics, usage tracking, or crash reporters, and the code is available under GPL-3.0.

A separate paid app from the same developer, DockDoor Pro, replaces the native macOS Dock entirely and adds profiles, widgets, and per-display Docks. It is sold as a one-time $20 purchase rather than a subscription. The free DockDoor described above adds to the existing Dock rather than replacing it.