{
  "type": "object",
  "properties": {
    "id": { "type": "string", "format": "uuid" },
    "kind": { "enum": ["order", "invoice", "shipment"] },
    "items": {
      "type": "array",
      "minItems": 1,
      "maxItems": 3,
      "items": {
        "type": "object",
        "properties": {
          "sku": { "type": "string" },
          "qty": { "type": "integer" },
          "status": { "enum": ["new", "backorder", "shipped"] },
          "notes": { "type": "string" }
        },
        "required": ["sku", "qty", "status", "notes"]
      }
    },
    "alt": {
      "oneOf": [
        { "type": "string" },
        { "type": "null" },
        { "type": "integer" }
      ]
    },
    "flags": {
      "type": "array",
      "minItems": 0,
      "maxItems": 4,
      "items": { "enum": ["fragile", "gift", "priority", "insured"] }
    },
    "meta": {
      "type": "object",
      "properties": {
        "created": { "type": "string", "format": "date-time" },
        "source": { "enum": ["api", "batch", "import"] },
        "ip": { "type": "string", "format": "ipv4" }
      },
      "required": ["created", "source", "ip"]
    },
    "priority": { "type": "integer" }
  },
  "required": ["id", "kind", "items", "alt", "flags", "meta", "priority"]
}