# POST /api/v1/client-messages/conversations/{conversation_id}/messages

> Reply to a conversation (client)

- **Tag:** client-messages
- **Operation ID:** `client_reply_api_v1_client_messages_conversations__conversation_id__messages_post`

## Description

Add a message to an existing conversation as a client.

## Authentication

Bearer token in `Authorization` header.
Required header: `x-business-id: <business uuid>`.

## Parameters

- `conversation_id` (path, string, required)

## Request body

Schema: `CreateMessageRequest`

- `body` (string · required) — Message body

## Responses

### 201 — Successful Response

Schema: `ConversationDetailResponse`

- `id` (string · required)
- `business_id` (string · required)
- `advisory_firm_id` (string · required)
- `subject` (string · required)
- `category` (ConversationCategory · required) → `ConversationCategory`
- `status` (ConversationStatus · required) → `ConversationStatus`
- `created_by_user_id` (string · required)
- `created_by_name` (string)
- `business_name` (string)
- `messages` (array · app__api__v1__schemas__client_messages__MessageResponse) → `app__api__v1__schemas__client_messages__MessageResponse`
  - `id` (string · required)
  - `conversation_id` (string · required)
  - `sender_user_id` (string · required)
  - `sender_role` (SenderRole · required) → `SenderRole`
  - `sender_name` (string)
  - `body` (string · required)
  - `read_at` (string · date-time)
  - `created_at` (string · date-time · required)
- `created_at` (string · date-time · required)
- `updated_at` (string · date-time · required)

### 400 — Bad Request - Invalid input

### 401 — Unauthorized - Authentication required

### 404 — Not Found - Resource does not exist

### 422 — Validation Error

Schema: `HTTPValidationError`

- `detail` (array · ValidationError) → `ValidationError`
  - `loc` (array · string | integer · required)
  - `msg` (string · required)
  - `type` (string · required)
  - `input` (object)
  - `ctx` (object)

## Code samples

### cURL

```bash
curl -X POST 'https://api.ondayzero.com/api/v1/client-messages/conversations/{conversation_id}/messages' \
  -H 'Authorization: Bearer dz_your_token' \
  -H 'x-business-id: YOUR_BUSINESS_ID' \
  -H 'Content-Type: application/json' \
  -d '{
  "body": "string"
}'
```

### JavaScript

```javascript
const response = await fetch('https://api.ondayzero.com/api/v1/client-messages/conversations/{conversation_id}/messages', {
  method: 'POST',
  headers: {
    Authorization: 'Bearer dz_your_token',
    'x-business-id': 'YOUR_BUSINESS_ID',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
  "body": "string"
}),
});
const data = await response.json();
```

### Python

```python
import httpx

headers = {
    "Authorization": "Bearer dz_your_token",
    "x-business-id": "YOUR_BUSINESS_ID",
}

payload = {
  "body": "string"
}

response = httpx.post("https://api.ondayzero.com/api/v1/client-messages/conversations/{conversation_id}/messages", headers=headers, json=payload)
data = response.json()
```

## See also

- HTML version: https://www.ondayzero.com/docs/reference/client-messages/client-reply
- OpenAPI slice: https://www.ondayzero.com/docs/reference/client-messages/client-reply/openapi.json
- Other endpoints in **client-messages**: https://www.ondayzero.com/docs/reference/client-messages