MagicBridge

A macOS menu bar app that lets you share a Magic Trackpad, Magic Mouse, or Magic Keyboard across multiple MacBooks — one click and the device switches to whichever Mac you're sitting at.

Features

• Menu Bar App — Runs silently in the menu bar, no dock icon
• Auto-Discovery — Finds other MacBooks running MagicBridge on your local network via mDNS/Bonjour, with a hello heartbeat protocol to stay in sync after sleep or network changes
• One-Click Handoff — Connect to any device with a single click; MagicBridge automatically asks the other Mac to release it first
• Graceful Fallback — If a peer doesn't respond in time, MagicBridge connects anyway and tells you
• Switch All — Move every enabled device to this Mac in one action
• Release All — Disconnect all devices from this Mac so another can pick them up
• Per-Device Enable/Disable — Toggle individual devices on or off; your choices are remembered across restarts
• Launch at Login — Optional auto-start so your devices are always ready when you log in
• No System Dialog — Device switching happens silently with no Bluetooth confirmation prompts

How It Works

Each Mac running MagicBridge does five things simultaneously:

1. Bluetooth monitoring — Listens for IOBluetooth connect/disconnect events for instant UI updates; a 60-second safety poll catches anything missed
2. mDNS advertising — Publishes a _magicbridge._tcp Bonjour record so other Macs can find it
3. Hello heartbeats — Sends a hello message to each known peer every 15 seconds (and immediately on wake from sleep); peers are evicted within 45 seconds if they go offline
4. Release protocol — When you click Connect or Switch All, MagicBridge sends a release_devices message over TCP (port 57842) to every peer; the peer disconnects the devices and replies devices_released before the local Mac connects
5. Silent pairing — After a device is released, MagicBridge uses IOBluetoothDevicePair with an auto-confirming delegate to re-establish the connection without showing any system dialog
6. Device persistence — Enabled devices are stored in UserDefaults so the list survives app restarts even when devices are off or out of range

Requirements

• macOS 13.0 or later
• Two or more Bluetooth-enabled Macs on the same local network
• Magic Trackpad, Magic Mouse, or Magic Keyboard

Installation

1. Download MagicBridge.zip from the latest release
2. Unzip and drag MagicBridge.app to your Applications folder
3. Launch it from Applications

First launch only: macOS will block the app because it is not notarized. Open System Settings → Privacy & Security, scroll down, and click Open Anyway. You will also be prompted to grant Bluetooth access — click Allow.

On first launch you'll be asked whether to enable Launch at Login. You can change this later by quitting and relaunching the app.

Building from Source

Prerequisites

• Xcode 15+
• XcodeGen (brew install xcodegen)

Build

# Install dependencies (xcodegen)
make deps

# Build and install directly to /Applications (no code signing required)
make install

# Release build — produces MagicBridge.app and MagicBridge.zip (requires a code signing identity)
make release

make install builds a debug binary, copies it to /Applications/MagicBridge.app, strips quarantine, and launches it immediately. make release produces a signed MagicBridge.app and MagicBridge.zip in the project root.

Usage

1. Click the menu bar icon to open the popover
2. Other MacBooks — Shows peers discovered on your network (green dot = reachable)
3. Devices — Lists all paired Magic devices
   • Click the circle to enable/disable a device (persisted across restarts)
   • Click Connect to claim the device on this Mac (peers are asked to release first)
   • Click Release to disconnect the device so another Mac can pick it up
4. Switch selected to this MacBook — Claim all enabled devices at once
5. Release all selected — Release all currently-connected enabled devices