CartoDB/cartodb20

{
  "type": "object",
  "required": ["colors"],
  "additionalProperties": false,
  "properties": {
    "prefix": { "type": "string" },
    "suffix": { "type": "string" },
    "left_label": { "type": "string" },
    "right_label": { "type": "string" },
    "colors": {
      "type": "array",
      "additionalProperties": false,
      "items": {
        "type": "object",
        "required": [
          "color"
        ],
        "additionalProperties": false,
        "properties": {
          "color": {
            "type": "string",
            "pattern": "^#(?:[0-9a-fA-F]{3}){1,2}$"
          }
        }
      }
    }
  }
}