Applies the Client’s Credit to an invoice

Request Parameters

Parameter Type Description Required
action string “ApplyCredit” Required
invoiceid int The ID of the invoice to apply credit Required
amount float string The amount of credit to apply to the invoice.
noemail bool Set to true to stop the invoice payment email being sent if the invoice becomes paid Optional

Response Parameters

Parameter Type Description
result string The result of the operation: success or error
invoiceid int The id of the invoice the credit has been applied to
amount float The amount of credit applied
invoicepaid string true/false string

Example Request (CURL)

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, '');
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS,
            'action' => 'ApplyCredit',
            // See
            'username' => 'IDENTIFIER_OR_ADMIN_USERNAME',
            'password' => 'SECRET_OR_HASHED_PASSWORD',
            'invoiceid' => '1',
            'amount' => '10.00',
            'responsetype' => 'json',
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$response = curl_exec($ch);

Example Request (Local API)

$command = 'ApplyCredit';
$postData = array(
    'invoiceid' => '1',
    'amount' => '10.00',
$adminUsername = 'ADMIN_USERNAME'; // Optional for WHMCS 7.2 and later

$results = localAPI($command, $postData, $adminUsername);

Example Response JSON

    "result": "success",
    "invoiceid": "1",
    "amount": "10.00",
    "invoicepaid": "false"

Error Responses

Possible error condition responses include:

  • Invoice ID Not Found
  • Invoice Not in Unpaid Status
  • Amount exceeds customer credit balance
  • Amount Exceeds Invoice Balance
  • Credit Amount to apply must be greater than zero

Version History

Version Changelog
1.0 Initial Version