MQTT Quality of Service 1 with the nRF Cloud library

RE: MQTT Quality of Service 1 with the nRF Cloud library

Pascal Hdz — Fri, 27 Mar 2026 09:21:27 GMT

Hello,

I'm closing this ticket for lack of response. Please open a new one in case you need further assistance.

Regards,

Pascal.

RE: MQTT Quality of Service 1 with the nRF Cloud library

Pascal Hdz — Wed, 25 Feb 2026 09:39:33 GMT

Hello,

Sorry for the late reply, have you figured out a solution or do you still need support on this matter?

Regards,

Pascal.

RE: MQTT Quality of Service 1 with the nRF Cloud library

oddgrd — Fri, 09 Jan 2026 15:46:06 GMT

Thank you, Benjamin! I did see that if I used the Zephyr MQTT library directly I would have access to these events and more control, but I was hoping that I could continue using the nRF Cloud library, as it significantly reduces the complexity of my application. And it seems to me that the MQTT helper library expects an MQTT client, and as I understand it I won't have access to the MQTT client directly when I use the nRF Cloud library.

Do you have a sample application using QoS-1 with the nRF Cloud library, which also listens for PUBACK and retries transmission? I linked one in my post, the `asset_tracker_v2` application, but it seemed quite convoluted, and it is deprecated in the newer versions of the SDK. I also noticed that you don't do it in the same way in the modern version of the example, the multi-service sample, so I assumed that it is not a recommended approach. However, in this sample you also set QoS to 1, but as far as I can tell, there is no logic to handle PUBACKs. To me that seems equivalent to setting QoS 0 when it comes to delivery guarantee, so I assume I am missing something. Is that correct?

Sorry for all the questions, but I've been digging into this for a while, and I struggled to find clear documentation for handling the various MQTT Quality of service settings on the application side. Perhaps the answer is just that I have to live with dropping the nRF cloud library, and drop down a level to the Zephyr MQTT library, as you suggested. I just want to make sure that is what I need to do before I get started, because it's a quite significant change in my firmware.

Edit: looking closer at the MQTT helper library, maybe I don't need to use the Zephyr MQTT library after all, but rather keep using the nRF cloud library for transmissions, and then just use the helper library to hook into PUBACKs. I'll see if that works, thanks!

RE: MQTT Quality of Service 1 with the nRF Cloud library

Benjamin — Fri, 09 Jan 2026 15:12:03 GMT

Hi,

These libraries do not automatically retransmit messages if no PUBACK is received. You need to handle this in the application. The MQTT helper library offer the on_puback callback to handle incoming PUBACKs. You will need to send again after some time.

You can also use MQTT Asynchronous Events that are notified to the application from the module through a callback registered in the application. See MQTT_EVT_PUBACK.

Regards,
Benjamin