What is rectangle?

Rectangle is a window management app for Mac that lets you quickly arrange and resize windows using keyboard shortcuts or by dragging windows to the edges of your screen. Instead of manually dragging windows around or using your mouse to resize them one pixel at a time, you can snap windows into preset positions with a single keystroke or gesture. The app works in two main ways. First, you can use keyboard shortcuts to instantly move a window to specific positions, like the left half of your screen, a corner, or a third of the screen. Second, you can drag a window toward the edge or corner of your screen, and Rectangle will show you a preview of where it will snap to when you release the mouse. This snap feature works for half-screen layouts, quarters, thirds, and other common window positions. You can turn off snapping if you prefer to stick to keyboard shortcuts. If you spend time switching between multiple applications or frequently need to see two windows side by side, Rectangle saves you from constant manual resizing. Developers, designers, and anyone who works with multiple windows simultaneously would find this useful. You can also customize every keyboard shortcut, ignore specific apps if you don't want Rectangle to affect them, and even trigger window actions through URLs or terminal commands. For power users, the app stores all your settings in a JSON file that you can backup or share across different Macs. Rectangle is free and open source, built in Swift (Apple's programming language), and works on recent versions of macOS. It's lightweight and runs quietly in the background, it won't slow down your Mac or get in the way unless you're actively using a window command.