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# Send a chat message

POST https://astropods.com/api/v1/deployments/{deploymentId}/messaging/conversations/{conversationId}/messages
Content-Type: application/json

Sends a user message to the agent. `attachments` contains ready Files API
keys owned by the caller; file bytes are never inlined. The sidecar reloads
authoritative metadata, persists the user turn, then forwards it to the
agent. The assistant reply streams over the SSE endpoint and is persisted as
it arrives. Subscribe to the stream endpoint for live chunks. A conversation
owned by another user returns 404.


Reference: https://docs.astropods.com/api-reference/astropods-api/chat/send-chat-message

## Authentication

- `Authorization` header (bearer token, required) — OAuth 2.0 device flow or platform session token

## Request

### Path parameters

- `deploymentId` (string, required) — Deployment ID
- `conversationId` (string, required) — Conversation ID (client-chosen UUID v4)

### Body (application/json)

This endpoint expects an object.

- `content` (string, optional) — The user's message text.
- `attachments` (list of object, optional) — Ready Files API keys owned by the caller. File bytes are not inlined.
  - `key` (string, required) — Opaque key of a ready file owned by the caller.

## Response

### 200

Message accepted (reply streams over the SSE endpoint)

- `message_id` (string, optional)
- `timestamp` (datetime, optional)

## Errors

### 400 Bad Request Error

Invalid request body or parameters

- `error` (string, optional)
- `details` (string, optional)

### 401 Unauthorized Error

Authentication required

- `error` (string, optional)
- `details` (string, optional)

### 403 Forbidden Error

Insufficient permissions for this account

- `error` (string, optional)
- `details` (string, optional)

### 404 Not Found Error

Resource not found

- `error` (string, optional)
- `details` (string, optional)

### 409 Conflict Error

The conversation has reached its per-thread message limit and is terminal. The response body carries the machine-readable code `message_limit_reached`; start a new conversation to continue.

- `error` (string, optional)
- `details` (string, optional)

### 413 Content Too Large Error

More than 16 files were attached to one message

- `error` (string, optional)
- `details` (string, optional)

### 500 Internal Server Error

Server error

- `error` (string, optional)
- `details` (string, optional)

## Examples

**Request**

```json
{}
```

**Response**

```json
{
  "message_id": "string",
  "timestamp": "2024-01-15T09:30:00Z"
}
```

**SDK Code**

```python
import requests

url = "https://astropods.com/api/v1/deployments/deploymentId/messaging/conversations/conversationId/messages"

payload = {}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.json())
```

```javascript
const url = 'https://astropods.com/api/v1/deployments/deploymentId/messaging/conversations/conversationId/messages';
const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: '{}'
};

try {
  const response = await fetch(url, options);
  const data = await response.json();
  console.log(data);
} catch (error) {
  console.error(error);
}
```

```go
package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://astropods.com/api/v1/deployments/deploymentId/messaging/conversations/conversationId/messages"

	payload := strings.NewReader("{}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(res)
	fmt.Println(string(body))

}
```

```ruby
require 'uri'
require 'net/http'

url = URI("https://astropods.com/api/v1/deployments/deploymentId/messaging/conversations/conversationId/messages")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{}"

response = http.request(request)
puts response.read_body
```

```java
import com.mashape.unirest.http.HttpResponse;
import com.mashape.unirest.http.Unirest;

HttpResponse<String> response = Unirest.post("https://astropods.com/api/v1/deployments/deploymentId/messaging/conversations/conversationId/messages")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{}")
  .asString();
```

```php
<?php
require_once('vendor/autoload.php');

$client = new \GuzzleHttp\Client();

$response = $client->request('POST', 'https://astropods.com/api/v1/deployments/deploymentId/messaging/conversations/conversationId/messages', [
  'body' => '{}',
  'headers' => [
    'Authorization' => 'Bearer <token>',
    'Content-Type' => 'application/json',
  ],
]);

echo $response->getBody();
```

```csharp
using RestSharp;

var client = new RestClient("https://astropods.com/api/v1/deployments/deploymentId/messaging/conversations/conversationId/messages");
var request = new RestRequest(Method.POST);
request.AddHeader("Authorization", "Bearer <token>");
request.AddHeader("Content-Type", "application/json");
request.AddParameter("application/json", "{}", ParameterType.RequestBody);
IRestResponse response = client.Execute(request);
```

```swift
import Foundation

let headers = [
  "Authorization": "Bearer <token>",
  "Content-Type": "application/json"
]
let parameters = [] as [String : Any]

let postData = JSONSerialization.data(withJSONObject: parameters, options: [])

let request = NSMutableURLRequest(url: NSURL(string: "https://astropods.com/api/v1/deployments/deploymentId/messaging/conversations/conversationId/messages")! as URL,
                                        cachePolicy: .useProtocolCachePolicy,
                                    timeoutInterval: 10.0)
request.httpMethod = "POST"
request.allHTTPHeaderFields = headers
request.httpBody = postData as Data

let session = URLSession.shared
let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
  if (error != nil) {
    print(error as Any)
  } else {
    let httpResponse = response as? HTTPURLResponse
    print(httpResponse)
  }
})

dataTask.resume()
```