sidecar.js

//In Node.js service
var nodemailer = require('nodemailer');
…
var kafka = require('kafka-node'),
    Consumer = kafka.Consumer,
    client = new kafka.Client(),
    consumer = new Consumer(client, [ { topic: 'platinum_emails', partition: 0 } ] );

consumer.on('message', function (orderConsumerTuple) {
    sendMail(orderConsumerTuple);
});