Introduction to custom WHMCS API functions

Are you not satisfied with default WHMCS API functions? In this little note I introduce you a very basic template for a custom API function.

First of all you should know every API function is a separate file stored at whmcs_folder/includes/api/.

So you should create you own file, all lowercase, same as your function name. For example yourcustomfunc.php

Also you need to know that:

The file dbconnect.php is included. This establishes a mysql connection.
The file includes/functions.php is included. This hold various WHMCS commands.

Security

You’ll need to make sure nobody can call your file directly.

if (!defined("WHMCS")) die("This file cannot be accessed directly");

Passing arguments to API function

All the parameters you passed via API call are available as $_POST variables

The next part is limited just by your fantasy. You can make queries, get/update/delete data as you want.

<?php
/* 
    Custom API Function 
    Name the file all lowercase and with the command to call 
    Save File To: /includes/api/
*/ 
if (!defined("WHMCS")) die("This file cannot be accessed directly");
?>

Good luck with extending WHMCS!