Serverless, websockets, only got 1 active connection


am testing an application using HiveMQ serverless MQTT over websockets. One publisher, multiple subscribers.
Can connect (both publisher and subscribers) and data flows, but if I have multiple subscribers only one of them receives the messages…

The subscribers use javascript in a webpage, the data goes to the last one to get refreshed.

Very weird, and not what I think it should do - unless there’s a limit on the serverless tier that I’ve missed?

Any suggestions? Don’t get any errors logged when the data stops flowing to a client, still thinks it’s connected…

Many thanks,


HI @JakeT
Greetings and a warm welcome to the HiveMQ Community! We’re thrilled to have you on board, and your enthusiasm for MQTT and the HiveMQ broker is truly appreciated.

To assist you more effectively, could you kindly provide the following details:

  1. Share the code of your clients.
  2. Specify each Client ID that your clients use.
  3. Indicate the specific topic or topics to which your clients subscribe.
  4. Clarify whether you can verify if your client has genuinely disconnected, or if there’s uncertainty in this regard.

Your cooperation with these details will greatly aid us in identifying and addressing the issues you’re facing. Thank you for reaching out, and we look forward to assisting you promptly.

Best regards,
Dasha from HiveMQ Team