How to Send a Message

Send a text message to a conversation. Carbon Voice will convert it to audio. Use the conversation_id from a webhook event to reply back to the same conversation. Note some endpoints may use channel_id instead of conversation_id, the value from either can be used.

POST /v6/messages/text
Content-Type: application/json

{
  "conversation_id": "string",
  "transcript": "string",
  "reply_to_message_id": "string",
  "idempotency_key": "string",
  "attachments": []
}

Request body fields:

Field	Description
`conversation_id`	The conversation to send to (use `conversation_id` from webhook).
`transcript`	The text content to send.
`reply_to_message_id`	The message ID to reply to (use `id` from webhook). Backend resolves the thread root automatically.
`idempotency_key`	A client-generated GUID used to de-duplicate repeated requests.
`attachments`	Optional array of attachment objects (files or links).

Response: Returns a message object containing id (the message_id).

Sending a Reply

Include reply_to_message_id to thread your reply under an existing message. The webhook payload exposes conversation_id and id — use these as conversation_id and reply_to_message_id in your request.

{
  "conversation_id": "<conversation_id from webhook>",
  "transcript": "Your reply here",
  "reply_to_message_id": "<id from webhook>",
  "idempotency_key": "<generated-guid>"
}