# 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 /v5/messages/text
Content-Type: application/json
```

```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.

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