MQTT,Sim800L General Questions

As it is my first time that i am trying to make something with MQTT i have some general questions that would like clarifying them from more skilled users

My setup will be an Arduino Nano with 3 Analog sensors and a SIM800L module transmitting MQTT messages to a Raspberry Pi, MQTT Mosquitto server and Node Red Server just to read the incoming messages (not interested in subscribe to my Arduino Nano )

1st Question : Are any libraries for MQTT with Sim800l module? (if i remember well i have found only for sim800 shields )

2nd Question : How should i send the sensors values? through just in one publish session with the topics or have to send each value in a different publish transmission to the server ?

thanks in advance

PS: i wasn't sure if i had to place my thread to this forum section or in the "Project Guidance" section. Sorry

Seems to me to be the right place to ask. You mention shields, so you are likely talking about the Adafruit sim808 or Botletics shields, but if not, check out the library Botletics wrote for his sim7000 shield at

It's basically a superset of the Adafruit library and it includes examples for MQTT. Get all the .pdfs, specifically the AT command references, for the sim7000 and sim700 modules and you'll see there is a lot of overlap between them.

I was using a sim808 and moved to a sim7000 without too much trouble. If I'd messed with MQTT for more than 2 hours or so I'd try to help more, but you probably know more than me. If you can't get the 800 to work, I'd consider just getting a sim7000 from aliExpress. It took a month to get to me, but only cost $25 (I'm in the US). Good luck!

Oh I'm talking about this breakout board, which runs on 5-10V, so that may not be what you need:

The bare module you can get for like $15 I think.