> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://docs.greenlane.ai/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.greenlane.ai/_mcp/server.

# Void

POST https://pos.fuel.greenlane.ai/gfp/void
Content-Type: application/json

The void API allows the POS to cancel an already authorized transaction.

1. Ensure the `transaction_id` and `payment_code` pair match a previously authorized transaction.
    
2. Only transactions that are in the authorized state may be voided.
    
3. Transactions that are already captured may not be voided.
    
4. The `transaction_time_ms` should be the epoch time in millis of when the customer cancelled the transaction.
    
5. Voided transactions may be safely voided again without side-effects.

Reference: https://docs.greenlane.ai/greenlane-fuel-platform/void

## Authentication

- `Authorization` header (bearer token, required)

## Request

### Body (application/json)

- `merchant_id` (string, required)
- `transaction_id` (string, required)
- `transaction_time_ms` (integer, required)
- `payment_code` (string, required)

## Response

### 200

OK

- `merchant_id` (string, required)
- `transaction_id` (string, required)
- `authorized_flag` (boolean, required)

## Examples

### Void successful

**Request**

```json
undefined
```

**Response**

```json
{
  "merchant_id": "merchant-123",
  "transaction_id": "123abcd",
  "authorized_flag": true
}
```

**SDK Code**

```python Void successful
import requests

url = "https://pos.fuel.greenlane.ai/gfp/void"

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

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

print(response.json())
```

```javascript Void successful
const url = 'https://pos.fuel.greenlane.ai/gfp/void';
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 Void successful
package main

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

func main() {

	url := "https://pos.fuel.greenlane.ai/gfp/void"

	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 Void successful
require 'uri'
require 'net/http'

url = URI("https://pos.fuel.greenlane.ai/gfp/void")

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 Void successful
import com.mashape.unirest.http.HttpResponse;
import com.mashape.unirest.http.Unirest;

HttpResponse<String> response = Unirest.post("https://pos.fuel.greenlane.ai/gfp/void")
  .header("Authorization", "Bearer <token>")
  .asString();
```

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

$client = new \GuzzleHttp\Client();

$response = $client->request('POST', 'https://pos.fuel.greenlane.ai/gfp/void', [
  'headers' => [
    'Authorization' => 'Bearer <token>',
  ],
]);

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

```csharp Void successful
using RestSharp;

var client = new RestClient("https://pos.fuel.greenlane.ai/gfp/void");
var request = new RestRequest(Method.POST);
request.AddHeader("Authorization", "Bearer <token>");
IRestResponse response = client.Execute(request);
```

```swift Void successful
import Foundation

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

let request = NSMutableURLRequest(url: NSURL(string: "https://pos.fuel.greenlane.ai/gfp/void")! 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()
```

### Authorization not found

**Request**

```json
undefined
```

**Response**

```json
{
  "merchant_id": "merchant-123",
  "transaction_id": "123abcd",
  "authorized_flag": false,
  "denied_reason": "Cannot find this transaction id."
}
```

**SDK Code**

```python Authorization not found
import requests

url = "https://pos.fuel.greenlane.ai/gfp/void"

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

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

print(response.json())
```

```javascript Authorization not found
const url = 'https://pos.fuel.greenlane.ai/gfp/void';
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 Authorization not found
package main

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

func main() {

	url := "https://pos.fuel.greenlane.ai/gfp/void"

	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 Authorization not found
require 'uri'
require 'net/http'

url = URI("https://pos.fuel.greenlane.ai/gfp/void")

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 Authorization not found
import com.mashape.unirest.http.HttpResponse;
import com.mashape.unirest.http.Unirest;

HttpResponse<String> response = Unirest.post("https://pos.fuel.greenlane.ai/gfp/void")
  .header("Authorization", "Bearer <token>")
  .asString();
```

```php Authorization not found
<?php
require_once('vendor/autoload.php');

$client = new \GuzzleHttp\Client();

$response = $client->request('POST', 'https://pos.fuel.greenlane.ai/gfp/void', [
  'headers' => [
    'Authorization' => 'Bearer <token>',
  ],
]);

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

```csharp Authorization not found
using RestSharp;

var client = new RestClient("https://pos.fuel.greenlane.ai/gfp/void");
var request = new RestRequest(Method.POST);
request.AddHeader("Authorization", "Bearer <token>");
IRestResponse response = client.Execute(request);
```

```swift Authorization not found
import Foundation

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

let request = NSMutableURLRequest(url: NSURL(string: "https://pos.fuel.greenlane.ai/gfp/void")! 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()
```

### Already captured

**Request**

```json
undefined
```

**Response**

```json
{
  "merchant_id": "merchant-123",
  "transaction_id": "123abcd",
  "authorized_flag": false,
  "denied_reason": "Cannot void transaction which is already captured."
}
```

**SDK Code**

```python Already captured
import requests

url = "https://pos.fuel.greenlane.ai/gfp/void"

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

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

print(response.json())
```

```javascript Already captured
const url = 'https://pos.fuel.greenlane.ai/gfp/void';
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 Already captured
package main

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

func main() {

	url := "https://pos.fuel.greenlane.ai/gfp/void"

	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 Already captured
require 'uri'
require 'net/http'

url = URI("https://pos.fuel.greenlane.ai/gfp/void")

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 Already captured
import com.mashape.unirest.http.HttpResponse;
import com.mashape.unirest.http.Unirest;

HttpResponse<String> response = Unirest.post("https://pos.fuel.greenlane.ai/gfp/void")
  .header("Authorization", "Bearer <token>")
  .asString();
```

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

$client = new \GuzzleHttp\Client();

$response = $client->request('POST', 'https://pos.fuel.greenlane.ai/gfp/void', [
  'headers' => [
    'Authorization' => 'Bearer <token>',
  ],
]);

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

```csharp Already captured
using RestSharp;

var client = new RestClient("https://pos.fuel.greenlane.ai/gfp/void");
var request = new RestRequest(Method.POST);
request.AddHeader("Authorization", "Bearer <token>");
IRestResponse response = client.Execute(request);
```

```swift Already captured
import Foundation

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

let request = NSMutableURLRequest(url: NSURL(string: "https://pos.fuel.greenlane.ai/gfp/void")! 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()
```

### Void_example

**Request**

```json
{
  "merchant_id": "merchant-123",
  "transaction_id": "123abcd",
  "transaction_time_ms": 1787636532000,
  "payment_code": "75123456"
}
```

**Response**

```json
{
  "merchant_id": "merchant-123",
  "transaction_id": "123abcd",
  "authorized_flag": true
}
```

**SDK Code**

```python Void_example
import requests

url = "https://pos.fuel.greenlane.ai/gfp/void"

payload = {
    "merchant_id": "merchant-123",
    "transaction_id": "123abcd",
    "transaction_time_ms": 1787636532000,
    "payment_code": "75123456"
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

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

print(response.json())
```

```javascript Void_example
const url = 'https://pos.fuel.greenlane.ai/gfp/void';
const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: '{"merchant_id":"merchant-123","transaction_id":"123abcd","transaction_time_ms":1787636532000,"payment_code":"75123456"}'
};

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

```go Void_example
package main

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

func main() {

	url := "https://pos.fuel.greenlane.ai/gfp/void"

	payload := strings.NewReader("{\n  \"merchant_id\": \"merchant-123\",\n  \"transaction_id\": \"123abcd\",\n  \"transaction_time_ms\": 1787636532000,\n  \"payment_code\": \"75123456\"\n}")

	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 Void_example
require 'uri'
require 'net/http'

url = URI("https://pos.fuel.greenlane.ai/gfp/void")

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 = "{\n  \"merchant_id\": \"merchant-123\",\n  \"transaction_id\": \"123abcd\",\n  \"transaction_time_ms\": 1787636532000,\n  \"payment_code\": \"75123456\"\n}"

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

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

HttpResponse<String> response = Unirest.post("https://pos.fuel.greenlane.ai/gfp/void")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"merchant_id\": \"merchant-123\",\n  \"transaction_id\": \"123abcd\",\n  \"transaction_time_ms\": 1787636532000,\n  \"payment_code\": \"75123456\"\n}")
  .asString();
```

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

$client = new \GuzzleHttp\Client();

$response = $client->request('POST', 'https://pos.fuel.greenlane.ai/gfp/void', [
  'body' => '{
  "merchant_id": "merchant-123",
  "transaction_id": "123abcd",
  "transaction_time_ms": 1787636532000,
  "payment_code": "75123456"
}',
  'headers' => [
    'Authorization' => 'Bearer <token>',
    'Content-Type' => 'application/json',
  ],
]);

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

```csharp Void_example
using RestSharp;

var client = new RestClient("https://pos.fuel.greenlane.ai/gfp/void");
var request = new RestRequest(Method.POST);
request.AddHeader("Authorization", "Bearer <token>");
request.AddHeader("Content-Type", "application/json");
request.AddParameter("application/json", "{\n  \"merchant_id\": \"merchant-123\",\n  \"transaction_id\": \"123abcd\",\n  \"transaction_time_ms\": 1787636532000,\n  \"payment_code\": \"75123456\"\n}", ParameterType.RequestBody);
IRestResponse response = client.Execute(request);
```

```swift Void_example
import Foundation

let headers = [
  "Authorization": "Bearer <token>",
  "Content-Type": "application/json"
]
let parameters = [
  "merchant_id": "merchant-123",
  "transaction_id": "123abcd",
  "transaction_time_ms": 1787636532000,
  "payment_code": "75123456"
] as [String : Any]

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

let request = NSMutableURLRequest(url: NSURL(string: "https://pos.fuel.greenlane.ai/gfp/void")! 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()
```