Using the AWS IoT SDK with ALPN extensions to connect over MQTTS on port 443

aws-iot-with-alpn.js

const client = require('aws-iot-device-sdk');

// The options object to provision the MQTT client with.
// Update values between chevrons with the appropriate values.
const opts = {
  host: "<aws-iot-endpoint>",
  keyPath: "<path-to-private-key>",
  certPath: "<path-to-device-certificate>",
  caPath: "<path-to-root-ca>",
  // We are specifying that we want to connect on the
  // port 443 of the AWS IoT Core broker.
  port: 443,
  // Enables the `x-amzn-mqtt-ca` protocol on the TLS connection.
  ALPNProtocols: ["x-amzn-mqtt-ca"]  
};

// Initiating the connection.
const mqttClient = client.device(opts);

// Listening for a connection event.
mqttClient.on('connect', () => console.log(`[+] Successfully connected to AWS IoT over the port ${opts.port}!`));

// Listening for an error event.
mqttClient.on('error', (err) => console.error('[!] An error occured during the connection', err));

ALPN is a feature only implemented onmqtts, since wss already uses port 443, you must not specify ALPNProtocols in the options when you connect (see the docs on available protocols and ports). The above example demonstrates how to connect to AWS IoT through mqtts using ALPN extensions.

I made an edit to the Gist description to make it clearer.