KeyGhost

What it does

KeyGhost is a macOS menu-bar app that transforms a keyboard key—Caps Lock, F-keys, Right Option, or any other modifier—into a launcher. When you hold the trigger key, a translucent keyboard overlay fades in showing app icons bound to each letter. Press a bound letter while holding the trigger, and the app launches immediately; the key chord is consumed and never reaches your focused window. The app reads the trigger key from the raw HID layer, beneath any modifier remapping, so it works regardless of Hyperkey, Karabiner, or macOS Modifier Keys.

KeyGhost supports nested radial menus: bind a letter to a root action plus four arrow-direction sub-actions (e.g., Caps+F opens Chrome; Caps+F+↑ opens Gmail; Caps+F+→ opens Calendar). It also offers a passthrough mode that rewrites event flags to the full ⌃⌥⇧⌘ chord before letting the key through, making it compatible with hotkeys for apps like Maccy, Raycast, or Shortcuts.app. The overlay shows live app icons resolved from NSWorkspace, and settings can be edited via a click-to-edit on-screen keyboard or by editing a JSON file that is live-watched.

Who it is for

KeyGhost is designed for macOS power users who prefer keyboard-driven workflows and want to reduce mouse dependency. It targets developers, writers, designers, and anyone who frequently launches apps or opens specific URLs (e.g., Gmail in Chrome, GitHub in Arc) and wants a faster, more customizable method than Spotlight, Raycast, or the Dock. The app is particularly useful for users who already use Hyperkey or Karabiner and need a launcher that works below those remapping layers.

Why it matters

Traditional app launchers require typing or clicking, which can interrupt flow. KeyGhost eliminates that friction by turning a single key hold into a visual, one-press launch. Its HID-layer detection ensures compatibility with any key remapping setup, solving a common pain point for users who have repurposed Caps Lock or other keys. The nested radial menus extend a single key binding to five destinations, reducing the number of chords needed. The passthrough mode preserves existing hotkey workflows, making KeyGhost a complementary tool rather than a replacement. The app is tiny, native (Swift, SwiftUI, no Electron), open source (MIT), and auto-updates via Sparkle.

Launch signal

KeyGhost is available as a signed and notarised DMG download from its website. The source code is on GitHub under the MIT license. The project appears to be a solo effort by Luke Boyle. There is no mention of funding, team size, or revenue. The website includes a live demo (using Space instead of Caps Lock due to browser limitations) and a video demonstration on a real keyboard.

Brand and naming

The name "KeyGhost" combines "key" (the trigger key) with "ghost" (the translucent overlay that appears and disappears). It is short, memorable, and evocative of the product's core functionality: a keyboard-driven launcher that feels invisible and fast. The domain keyghost.dev reinforces the developer-focused audience. The branding is minimal and functional, matching the app's no-nonsense utility.