Sunday, October 7, 2018

Configuring MQTT JavaScript client for


I had to struggle to make my MQTT Javascript code to work in a browser.  So here it is.
  • I am using the provider free plan from
  1. Create a MQTT broker using the free plan 
  2. I used the Websockets Port 
  3. The url must be formatted this way: 'wss://'
  4. In the connection options, useSSL must be true
this._options = {
    port: webSocketPort, // Required for WebSocket
    useSSL: true,        // Required for WebSocket
    host: mqttUrl,
    keepalive: 60,
    reconnectPeriod: 1000,
    protocolId: 'MQIsdp',
    protocolVersion: 3,
    clean: true,
    encoding: 'utf8'

this._client = mqtt.connect(, this._options);

Source code

Here the full source code for JavaScript and C#. The Javascript code was testing on
Chrome Windows and iOS, Edge and IE11.

All project MQTTManager on Github

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