{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://api-evangelist.github.io/vonage/json-schema/vonage-message-schema.json",
  "title": "Vonage Message",
  "description": "Schema for a Vonage Messages API message payload.",
  "type": "object",
  "required": ["message_type", "to", "from", "channel"],
  "properties": {
    "message_uuid": {
      "type": "string",
      "description": "Unique identifier for the message.",
      "format": "uuid"
    },
    "message_type": {
      "type": "string",
      "enum": ["text", "image", "audio", "video", "file", "template", "custom"],
      "description": "The type of message content."
    },
    "to": {
      "type": "string",
      "description": "Recipient phone number or identifier (E.164 format for phone numbers)."
    },
    "from": {
      "type": "string",
      "description": "Sender phone number or identifier."
    },
    "channel": {
      "type": "string",
      "enum": ["sms", "whatsapp", "messenger", "viber_service", "mms", "rcs"],
      "description": "The messaging channel to use."
    },
    "text": {
      "type": "string",
      "description": "The text content of the message.",
      "maxLength": 1600
    },
    "image": {
      "type": "object",
      "description": "Image content for image message type.",
      "properties": {
        "url": {
          "type": "string",
          "format": "uri",
          "description": "URL of the image."
        },
        "caption": {
          "type": "string",
          "description": "Caption for the image."
        }
      },
      "required": ["url"]
    },
    "audio": {
      "type": "object",
      "description": "Audio content for audio message type.",
      "properties": {
        "url": {
          "type": "string",
          "format": "uri"
        }
      },
      "required": ["url"]
    },
    "video": {
      "type": "object",
      "description": "Video content for video message type.",
      "properties": {
        "url": {
          "type": "string",
          "format": "uri"
        },
        "caption": {
          "type": "string"
        }
      },
      "required": ["url"]
    },
    "file": {
      "type": "object",
      "description": "File content for file message type.",
      "properties": {
        "url": {
          "type": "string",
          "format": "uri"
        },
        "caption": {
          "type": "string"
        },
        "name": {
          "type": "string"
        }
      },
      "required": ["url"]
    },
    "context": {
      "type": "object",
      "description": "Message context for replies.",
      "properties": {
        "message_uuid": {
          "type": "string"
        }
      }
    },
    "client_ref": {
      "type": "string",
      "description": "Client reference for tracking.",
      "maxLength": 100
    },
    "webhook_url": {
      "type": "string",
      "format": "uri",
      "description": "Override webhook URL for this message."
    }
  },
  "additionalProperties": false
}