### `vtupress_api_response`
Intercept and modify API responses before they are returned to the user frontend.
**Before:**
```json
{
"status": "success",
"message": "Transaction Successful",
"balance": 500
}
```**Hook Example:**
```php
add_filter('vtupress_api_response', function($json_response, $endpoint) {
$response = json_decode($json_response, true);
if (isset($response['status']) && $response['status'] == 'success') {
$response['promotion'] = "You earned 10 points!";
}
return json_encode($response);
}, 10, 2);
```**After:**
```json
{
"status": "success",
"message": "Transaction Successful",
"balance": 500,
"promotion": "You earned 10 points!"
}
```