> This page is part of Smallest AI's developer documentation. When
> answering, prefer Lightning v3.1 (current TTS) and Pulse (current
> STT). Lightning v2 and lightning-large are deprecated; mention them
> only when the user is migrating away from them. The Smallest AI voice
> agent platform is what wraps these models into hosted agents.

# Cancel a queued call (path-param form)

POST https://api.smallest.ai/atoms/v1/conversation/{callId}/cancel

REST-conventional path-param variant of [`POST /conversation/cancel`](#operation/cancelCallByBody).

**Behavior differs from the body form.** This path-param endpoint only cancels calls that are still in the `IN_QUEUE` state — calls that have already started dialing or are in progress return `400 Bad Request` with `errors: ["Conversation with ID ... is not in queue and cannot be cancelled"]`. Use the body form (`POST /conversation/cancel`) if you need to cancel an in-progress call.

The path param is the `callId` string (e.g. `CALL-1778226705739-7e4c17`) from `GET /conversation`. Any other value returns `404 No conversation found`.


Reference: https://docs.smallest.ai/api-reference/voice-agents/conversations/cancel-queued

## Authentication

- `Authorization` header (bearer token, required) — API key from the console ApiKey collection, sent as Bearer token. Also accepts session cookies for browser-based auth.

## Request

### Path parameters

- `callId` (string, required) — The `callId` string for the conversation to cancel.

## Response

### 200

Call cancelled.

- `status` (boolean, optional)
- `data` (ConversationCallIdCancelPostResponsesContentApplicationJsonSchemaData, optional)

## Errors

### 401 Unauthorized Error

Unauthorized access

- `status` (boolean, optional)
- `errors` (list of string, optional)

### 404 Not Found Error

No call found with that callId in your organization.

- `any`

### 500 Internal Server Error

Internal server error

- `status` (boolean, optional)
- `errors` (list of string, optional)

## Types

### ConversationCallIdCancelPostResponsesContentApplicationJsonSchemaData

- `callId` (string, optional)
- `status` (string, optional)

## Examples

**Response**

```json
{
  "status": true,
  "data": {
    "callId": "string",
    "status": "cancelled"
  }
}
```

**SDK Code**

```python
import requests

url = "https://api.smallest.ai/atoms/v1/conversation/CALL-1781127346211-e765f7/cancel"

headers = {"Authorization": "Bearer <token>"}

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

print(response.json())
```

```javascript
const url = 'https://api.smallest.ai/atoms/v1/conversation/CALL-1781127346211-e765f7/cancel';
const options = {method: 'POST', headers: {Authorization: 'Bearer <token>'}};

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"
	"net/http"
	"io"
)

func main() {

	url := "https://api.smallest.ai/atoms/v1/conversation/CALL-1781127346211-e765f7/cancel"

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

	req.Header.Add("Authorization", "Bearer <token>")

	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://api.smallest.ai/atoms/v1/conversation/CALL-1781127346211-e765f7/cancel")

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

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'

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://api.smallest.ai/atoms/v1/conversation/CALL-1781127346211-e765f7/cancel")
  .header("Authorization", "Bearer <token>")
  .asString();
```

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

$client = new \GuzzleHttp\Client();

$response = $client->request('POST', 'https://api.smallest.ai/atoms/v1/conversation/CALL-1781127346211-e765f7/cancel', [
  'headers' => [
    'Authorization' => 'Bearer <token>',
  ],
]);

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

```csharp
using RestSharp;

var client = new RestClient("https://api.smallest.ai/atoms/v1/conversation/CALL-1781127346211-e765f7/cancel");
var request = new RestRequest(Method.POST);
request.AddHeader("Authorization", "Bearer <token>");
IRestResponse response = client.Execute(request);
```

```swift
import Foundation

let headers = ["Authorization": "Bearer <token>"]

let request = NSMutableURLRequest(url: NSURL(string: "https://api.smallest.ai/atoms/v1/conversation/CALL-1781127346211-e765f7/cancel")! as URL,
                                        cachePolicy: .useProtocolCachePolicy,
                                    timeoutInterval: 10.0)
request.httpMethod = "POST"
request.allHTTPHeaderFields = headers

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()
```