How to send MQTT packets to a custom server application

Yes, this is the way to forward your decrypted chirpstack data to another application. If you want to use the MQTT integration you just need to configure the server= line in the [integration.mqtt] section. Alternatively you could just have your separate application subscribe to your MQTT broker and pull the data from there.

But let me just confirm a few things about your setup / goal:

  • Your goal is to not change how Chirpstack is currently functioning, just to pass the unencrypted sensor data to a different application.
  • You are currently using your Pi as a gateway and the main Chirpstack server.
  • Do you have Chirpstack Gateway OS full installed on your Pi? Or did you do a Ubuntu/docker?

Unfortunately, the gateway OS full is flawed for the MQTT integration - MQTT integration with application server - #19 by Liam_Philipp. I put out a pull request to fix this a while ago but no response. If you are using this I’d recommend just doing a different integration like HTTP that you can configure through the UI. Or making your Pi just a gateway and using Chirpstack on a different server.