{
  "api_base": "https://signage.example.com",
  "api_token": "st_REPLACE_WITH_A_FULL_SCOPE_TOKEN",
  "overlay_base_url": "https://signage.example.com/message-overlay.html",

  "device_id": "DEVICE_OR_GROUP_ID",
  "default_title": "NOTICE",

  "overlay": {
    "position": "center",
    "width": 900,
    "height": 300,
    "border_radius": 16,
    "color": "#CC0000",
    "duration": 0
  }
}