GridSnap: A Free, Open-Source Window Manager for macOS

Developer

GridSnap is designed as a community-driven, open-source alternative to Divvy, providing macOS users with a flexible way to organize their workspace. Instead of static layouts, it utilizes a dynamic grid system to snap windows into place.

🚀 Core Functionality

The basic workflow is intuitive: trigger a shortcut, select your desired area on a visual grid, and the window snaps instantly.

Key Features

Interactive Preview: The window follows your cursor in real-time as you drag across the grid; if you cancel, it jumps back to its original spot.
Custom Presets: Save specific regions to trigger them with a single keystroke.
- Example: A built-in full-screen preset is mapped to $\text{Ctrl} + \text{Opt} + F$ .
Flexibility:
- Undo/Redo the last snap using $\text{Ctrl} + \text{Opt} + Z$ .
- Adjustable grid dimensions (rows/columns) and the gap (in points) between windows.
- Choose whether to snap the focused window or the one under the cursor.
System Integration:
- Supports multiple monitors (the grid appears on the display where your cursor is located).
- Runs as a menu bar application with "Launch at Login" support.
- ~~No network access~~, ~~no analytics~~, and ~~no account requirements~~.
- No distracting Dock icon.

Compatibility Note: Requires macOS 14 or later. While tested on macOS 26, users on older versions will see a frosted panel instead of the modern glass material for the grid.

🛠 Installation Guide

You can get GridSnap running via several methods:

Via Homebrew: brew install --cask konieczkow/tap/gridsnap
Manual Install: Download the GridSnap-x.y.z.zip from the latest release, extract it, and move the app to your /Applications folder.

Build from Source:

git clone https://github.com/konieczkow/gridsnap.git
cd gridsnap
./build.sh install
open /Applications/GridSnap.app

⚠️ Essential Permissions

Because GridSnap manipulates other applications, it requires Accessibility permissions.

Navigate to System Settings $\rightarrow$ Privacy & Security $\rightarrow$ Accessibility.
Toggle GridSnap ON. (Tip: You can also click "Grant Accessibility..." in the menu bar icon to jump straight to this menu).

⌨️ Usage & Controls

Action	Command / Input	Description
Show Grid	$\text{Ctrl} + \text{Opt} + D$	Opens the snapping overlay (configurable).
Snap Window	`Click` or `Drag`	Select cells and release to snap.
Cancel	`Esc`	Dismisses the grid without changes.
Save Preset	`Shift` + `Release`	Saves the current selection as a preset.
Apply Preset	`Custom Shortcut`	Instantly snaps to a saved region.
Undo/Redo	$\text{Ctrl} + \text{Opt} + Z$	Reverts or reapplies the last snap.

⚙️ Configuration & Development

Access the Settings via the menu bar icon. Here you can modify:

Global shortcuts.
Grid layout (columns/rows) and window gaps.
The target rule for window selection.
The presets table (names and shortcuts are editable in-place; use the − button to delete).

Technical Architecture

The project is written in Swift. Key files in Sources/ include:

main.swift: Application startup.
AX.swift: Handles the Accessibility API plumbing.
Grid.swift: Manages the visual overlay.
Presets.swift & Hotkeys.swift: Handle saved layouts and keyboard listeners.
SettingsWindow.swift & Menu.swift: UI components.
Defaults.swift: Manages persistent settings.

Developer's Note on Code Signing

macOS links Accessibility permissions to the app's signature.

Ad-hoc signatures change every build, forcing you to re-grant permissions constantly.
Solution: Create a self-signed "Code Signing" certificate named GridSnap Dev in Keychain Access. The build script will detect this automatically.
Alternatively, use: CODESIGN_IDENTITY="your_name" ./build.sh.

Note on Limitations: Some applications enforce a minimum window size. If a cell is smaller than the app's limit, the window will overlap adjacent cells.