Runtime.ImportModuleError with mqttjs when deployed

Hello, I am using netlify’s amazing functions to make a bridge between a webapp and an MQTT broker. The idea is to send a POST req to it and lamda does the talking and then ends the connection. The code is pretty simple and works locally using netlify-lambda.

I am using these settings : netlify-lambda build functions --config ./config/webpack.functions.js
as i read them here.

When I deploy it i get an error on the functions console -
ERROR Uncaught Exception {"errorType":"Runtime.ImportModuleError","errorMessage":"Error: Cannot find module 'mqtt'\nRequire stack:\n- /var/task/test.js\n- /var/runtime/UserFunction.js\n- /var/runtime/index.js","stack":["Runtime.ImportModuleError: Error: Cannot find module 'mqtt'","Require stack:","- /var/task/test.js","- /var/runtime/UserFunction.js","- /var/runtime/index.js"," at _loadUserApp (/var/runtime/UserFunction.js:100:13)"," at Object.module.exports.load (/var/runtime/UserFunction.js:140:17)"," at Object.<anonymous> (/var/runtime/index.js:43:30)"," at Module._compile (internal/modules/cjs/loader.js:955:30)"," at Object.Module._extensions..js (internal/modules/cjs/loader.js:991:10)"," at Module.load (internal/modules/cjs/loader.js:811:32)"," at Function.Module._load (internal/modules/cjs/loader.js:723:14)"," at Function.Module.runMain (internal/modules/cjs/loader.js:1043:10)"," at internal/main/run_main_module.js:17:11"]}

I think somehow its not getting the mqtt.js dependency. What am I missing?
I followed this tutorial to get started.

my script is like this.
import mqtt from ‘mqtt’

exports.handler=function(event, context, callback){
const params= JSON.parse(event.body);
const mqttTopic = params.mqttTopic+’/cardID’;
const cardID=;

var options={
    port: xxxxxx};

//Send back response to user
const send = body =>
statusCode: 200,
headers: {
‘Access-Control-Allow-Headers’ :‘Origin,X-Requested-With,Content-Type,Accept’
body : JSON.stringify({ msg : mqttTopic, data: cardID})

//Send unlock command to the HUD
const sendData =()=>
var client = mqtt.connect(“mqtt://”,options)



//Check if its a valid response
if(event.httpMethod == ‘POST’)


Thanks a lot :slight_smile:

Hi @IndianTinker, it looks like you are using netlify-lambda and are bundling your function. Could you try using our buildbot’s built-in zip-it-and-ship-it feature instead? To use it, you’ll remove the neltify-lambda build command and just make sure you npm i inside your function’s folder if you have a package.json file there. For more information on how zip-it-and-ship-it works, you can go here: (just note that this is already built in to our builtbot and you don’t have to do any installing to use it).

Let me know if that helps.