Take the demo REST client and edit it this way: <?php /** * REST client for Moodle 2 * Return JSON or XML format * * @authorr Jerome Mouneyrac */   /// SETUP - NEED TO BE CHANGED $token = 'f95fe8ce5f6a4f01dc24ccdf333bba22'; $domainname = 'http://jerome.moodle.local/~jerome/Moodle_HEAD';   $functionname = 'core_enrol_get_enrolled_users';   // REST RETURNED VALUES FORMAT $restformat = 'json'; //Also possible in Moodle 2.2 and later: 'json' //Setting it to 'json' will fail all calls on earlier Moodle version   //////// moodle_user_create_users ////////   /// PARAMETERS - NEED TO BE CHANGED TO TEST DIFFERENT CASES $params = array('courseid' => 2, //CHANGE IT 'options' => array( array('name' => 'limitfrom', 'value' => 5), //CHANGE VALUE, REMOVE OPTION array('name' => 'limitnumber', 'value' => 4) //CHANGE VALUE, REMOVE OPTION ) );   /// REST CALL header('Content-Type: text/plain'); $serverurl = $domainname . '/webservice/rest/server.php'. '?wstoken=' . $token . '&wsfunction='.$functionname; require_once('./curl.php'); $curl = new curl; //if rest format == 'xml', then we do not add the param for backward compatibility with Moodle < 2.2 $restformat = ($restformat == 'json')?'&moodlewsrestformat=' . $restformat:''; $resp = $curl->post($serverurl . $restformat, $params); print_r($resp); Without 'limitfrom' and 'limitnumber' the web service function should return all enrolled users in the course. With limitfrom and limitnumber you should be able to limit the number of returned users.