VerneMQ supports the WebSocket protocol out of the box. To be able to open a WebSocket connection to VerneMQ, you have to configure a WebSocket listener or Secure WebSocket listener in the vernemq.conf file first:

listener.ws.default =

listener.wss.default =

Keep in mind that you'll use MQTT-over-WebSocket, so you will need a Javascript library that implements the MQTT client behaviour. We have used the Eclipse Paho client as well as MQTT.js

You won't be able to open WebSocket connections on a base URL, always add the /mqtt path.