"; if (strpos($message_body, 'HELP') !== false) { echo "Send STATUS {id} to get order status. Send HELP for more info."; } else if (strpos($message_body, 'STATUS') !== false) { // Actual order status calculation is requred. $order_status = "pending delivery"; echo "Your order status is {$order_status}"; } else { // You could say unsuported keyword here. We're going to just repeat HELP. echo "Send STATUS {id} to get order status. Send HELP for more info."; } // Close main InboundXML tag echo "";