Multiboxer configuration quick start

This guide creates a simple five-client configuration for one 3840 x 2160 display. One client uses the large left side of the display. Four smaller clients are stacked on the right.

Use the configuration guide when you want to understand the layout or add features. See the complete reference for every option.

Where the configuration is stored

The installed application normally uses:

%APPDATA%\MultiBoxer\config\default.json

The Config button opens the active file in Notepad. You can also start Multiboxer with a different JSON file as its first command-line argument.

Before you edit

JSON has a few strict rules:

• Put double quotes around property names and text values.
• Separate entries with commas, but do not put a comma after the last entry.
• Write a Windows backslash as two backslashes, for example C:\\Games\\MyGame.
• JSON does not support comments.
• Names are references. A region or instance name must be spelled consistently everywhere.

Complete starter configuration

Copy this example and change the five executable paths. The layout is 2880 x 2160 for the main client and four 960 x 540 clients on the right.

{
  "inject_virtual_mouse_dll": false,
  "remove_registry_settings_at_startup": false,
  "debug": false,
  "regions": [
    {
      "name": "main",
      "display": "0",
      "region": { "x": 0, "y": 0, "width": 2880, "height": 2160 }
    },
    {
      "name": "client2",
      "display": "0",
      "region": { "x": 2880, "y": 0, "width": 960, "height": 540 }
    },
    {
      "name": "client3",
      "display": "0",
      "region": { "x": 2880, "y": 540, "width": 960, "height": 540 }
    },
    {
      "name": "client4",
      "display": "0",
      "region": { "x": 2880, "y": 1080, "width": 960, "height": 540 }
    },
    {
      "name": "client5",
      "display": "0",
      "region": { "x": 2880, "y": 1620, "width": 960, "height": 540 }
    }
  ],
  "main_region": "main",
  "instances": [
    {
      "name": "game1",
      "executable": "C:\\Games\\MyGame\\1\\Game.exe",
      "region": "main"
    },
    {
      "name": "game2",
      "executable": "C:\\Games\\MyGame\\2\\Game.exe",
      "region": "client2"
    },
    {
      "name": "game3",
      "executable": "C:\\Games\\MyGame\\3\\Game.exe",
      "region": "client3"
    },
    {
      "name": "game4",
      "executable": "C:\\Games\\MyGame\\4\\Game.exe",
      "region": "client4"
    },
    {
      "name": "game5",
      "executable": "C:\\Games\\MyGame\\5\\Game.exe",
      "region": "client5"
    }
  ],
  "keymaps": [
    {
      "name": "number_keys",
      "keys": ["1", "2", "3", "4", "5", "6", "7", "8", "9", "0"],
      "actions": [
        [
          { "action": "forward" }
        ]
      ]
    },
    {
      "name": "mouse_broadcast",
      "keys": ["Ctrl+M"],
      "actions": [
        [
          { "action": "mouse_broadcast", "mouse_broadcast_mode": "toggle" }
        ]
      ]
    }
  ]
}

What this configuration does

Multiboxer launches five copies of the game and moves each window into its region. Pressing a number key from 0 through 9 forwards that key to all five managed clients. Pressing Ctrl+M toggles continuous mouse broadcasting.

The example disables virtual-mouse DLL injection because it is an advanced compatibility feature. It also leaves the capture compositor disabled; the four smaller clients are normal game windows.

Adapt it to your display

Region coordinates start at the display's top-left corner:

x increases to the right
y increases downward
width is the region width in pixels
height is the region height in pixels

Every instance must initially own a different region, and one instance must own main_region.

Add another forwarded key

Add it to the keys list:

"keys": ["1", "2", "3", "4", "5", "6", "7", "8", "9", "0", "Space"]

All recognized names are listed in keys and actions.

Start safely

Test with harmless applications or game menus first. Confirm window positions, number-key forwarding, and mouse behavior before using more powerful mappings such as any, swapping, or state-changing actions.