Checkout dev branch Download the attached PHP-XMLRPC.zip test client and unzip it into Moodle root directory Install and configure Moodle (admin user, site ...) Enable web services - see: Using web services Create a new external webservice adding all core Moodle web services Create a token for new external webservice for admin user In another browser window (tab) navigate to: yoursite/PHP-XMLRPC/client.php Enter the following: Token : use the token created above URL : use your site's base URL Method : core_user_delete_users Data : {"userids":[0]} and submit the query ... Received data should be (something like): array(2) { ["faultCode"]=> int(28194976) ["faultString"]=> string(55) "Calling parameters do not match signature | ERRORCODE: " }