> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://docs.crisscross.money/api-reference/collect/payments/manage-payments/cancel-transaction/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.crisscross.money/_mcp/server.

# Cancel a Transaction

POST https://api.crisscross.money/v1/payment/{transactionId}/cancel
Content-Type: application/json

Cancels a single transaction by its identifier. The transaction is the only thing affected — the session it belongs to remains active, and any other transactions on the session continue normally.

A transaction can only be cancelled while it is in a non-terminal state and while the originating provider supports cancelling an in-progress transaction. Otherwise the call returns `409`.


Reference: https://docs.crisscross.money/api-reference/collect/payments/manage-payments/cancel-transaction

## Request

### Path parameters

- `transactionId` (string, required) — Identifier of the transaction to cancel. UUID v7.

### Body (application/json)

This endpoint expects a CancelTransactionRequest.

- `reason` (string, optional) — Optional free-form reason for the cancellation, recorded for reporting.

## Response

### 200

Transaction cancelled.

- `transactionId` (string, required) — Identifier of the cancelled transaction. UUID v7.
- `status` (enum, required) — The resulting state of the transaction.
  - Allowed values: `CANCELLED`
- `message` (string, required) — Human-readable status message.

## Errors

### 400 Bad Request Error

Invalid request parameters.

- `message` (string, required) — Human-readable description of what went wrong.
- `error` (string, required) — Error category. Most endpoints return the HTTP reason phrase (e.g. "Bad Request", "Unauthorized", "Conflict", "Unprocessable Entity", "Internal Server Error"). Some return a machine-readable snake_case code instead — notably the FX and rate-lock rejections on checkout session creation and payment initiation, where several distinct codes share a single HTTP status. Where a code is present it is the finer discriminator and is safe to branch on.
- `statusCode` (integer, required) — HTTP status code, mirroring the response header. The response header is the source of truth.

### 401 Unauthorized Error

Unauthorized.

- `message` (string, required) — Human-readable description of what went wrong.
- `error` (string, required) — Error category. Most endpoints return the HTTP reason phrase (e.g. "Bad Request", "Unauthorized", "Conflict", "Unprocessable Entity", "Internal Server Error"). Some return a machine-readable snake_case code instead — notably the FX and rate-lock rejections on checkout session creation and payment initiation, where several distinct codes share a single HTTP status. Where a code is present it is the finer discriminator and is safe to branch on.
- `statusCode` (integer, required) — HTTP status code, mirroring the response header. The response header is the source of truth.

### 404 Not Found Error

Transaction not found.

- `message` (string, required) — Human-readable description of what went wrong.
- `error` (string, required) — Error category. Most endpoints return the HTTP reason phrase (e.g. "Bad Request", "Unauthorized", "Conflict", "Unprocessable Entity", "Internal Server Error"). Some return a machine-readable snake_case code instead — notably the FX and rate-lock rejections on checkout session creation and payment initiation, where several distinct codes share a single HTTP status. Where a code is present it is the finer discriminator and is safe to branch on.
- `statusCode` (integer, required) — HTTP status code, mirroring the response header. The response header is the source of truth.

### 409 Conflict Error

Conflict — the transaction is already in a terminal state, or the originating provider does not support cancelling it at this stage.

- `message` (string, required) — Human-readable description of what went wrong.
- `error` (string, required) — Error category. Most endpoints return the HTTP reason phrase (e.g. "Bad Request", "Unauthorized", "Conflict", "Unprocessable Entity", "Internal Server Error"). Some return a machine-readable snake_case code instead — notably the FX and rate-lock rejections on checkout session creation and payment initiation, where several distinct codes share a single HTTP status. Where a code is present it is the finer discriminator and is safe to branch on.
- `statusCode` (integer, required) — HTTP status code, mirroring the response header. The response header is the source of truth.

### 422 Unprocessable Entity Error

Unprocessable Entity.

- `message` (string, required) — Human-readable description of what went wrong.
- `error` (string, required) — Error category. Most endpoints return the HTTP reason phrase (e.g. "Bad Request", "Unauthorized", "Conflict", "Unprocessable Entity", "Internal Server Error"). Some return a machine-readable snake_case code instead — notably the FX and rate-lock rejections on checkout session creation and payment initiation, where several distinct codes share a single HTTP status. Where a code is present it is the finer discriminator and is safe to branch on.
- `statusCode` (integer, required) — HTTP status code, mirroring the response header. The response header is the source of truth.

## Examples

**Request**

```json
{
  "reason": "Customer requested cancellation"
}
```

**Response**

```json
{
  "transactionId": "01951c8a-8b4c-7d2a-8f1e-5d6c7b8a9e10",
  "status": "CANCELLED",
  "message": "Transaction cancelled."
}
```

**SDK Code**

```python
import requests

url = "https://api.crisscross.money/v1/payment/transactionId/cancel"

payload = { "reason": "Customer requested cancellation" }
headers = {"Content-Type": "application/json"}

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

print(response.json())
```

```javascript
const url = 'https://api.crisscross.money/v1/payment/transactionId/cancel';
const options = {
  method: 'POST',
  headers: {'Content-Type': 'application/json'},
  body: '{"reason":"Customer requested cancellation"}'
};

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://api.crisscross.money/v1/payment/transactionId/cancel"

	payload := strings.NewReader("{\n  \"reason\": \"Customer requested cancellation\"\n}")

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

	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://api.crisscross.money/v1/payment/transactionId/cancel")

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

request = Net::HTTP::Post.new(url)
request["Content-Type"] = 'application/json'
request.body = "{\n  \"reason\": \"Customer requested cancellation\"\n}"

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.crisscross.money/v1/payment/transactionId/cancel")
  .header("Content-Type", "application/json")
  .body("{\n  \"reason\": \"Customer requested cancellation\"\n}")
  .asString();
```

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

$client = new \GuzzleHttp\Client();

$response = $client->request('POST', 'https://api.crisscross.money/v1/payment/transactionId/cancel', [
  'body' => '{
  "reason": "Customer requested cancellation"
}',
  'headers' => [
    'Content-Type' => 'application/json',
  ],
]);

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

```csharp
using RestSharp;

var client = new RestClient("https://api.crisscross.money/v1/payment/transactionId/cancel");
var request = new RestRequest(Method.POST);
request.AddHeader("Content-Type", "application/json");
request.AddParameter("application/json", "{\n  \"reason\": \"Customer requested cancellation\"\n}", ParameterType.RequestBody);
IRestResponse response = client.Execute(request);
```

```swift
import Foundation

let headers = ["Content-Type": "application/json"]
let parameters = ["reason": "Customer requested cancellation"] as [String : Any]

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

let request = NSMutableURLRequest(url: NSURL(string: "https://api.crisscross.money/v1/payment/transactionId/cancel")! 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()
```