{
  "actions": [
    {
      "id": "SETFILLCOLOR",
      "type": "ExecuteFunction",
      "name": "Cell Fill Colors"
    }
  ],
  "shortcuts": [
    {
      "action": "SETFILLCOLOR",
      "key": {
        "default": "Ctrl+shift+4"
      }
    }
  ]
}

This is my current shortcuts json data. This also implement in my excel web add in. But now trying to implement shortcuts using special character.

{
  "actions": [
    {
      "id": "SETFILLCOLOR",
      "type": "ExecuteFunction",
      "name": "Cell Fill Colors"
    }
  ],
  "shortcuts": [
    {
      "action": "SETFILLCOLOR",
      "key": {
        "default": "Ctrl+Shift+$"
      }
    }
  ]
}