Mqtt Client Reconnect

In this tutorial, you'll learn about MQTT Client Reconnect Not Working. We cover key concepts, practical examples, and best practices.

The Problem

Client does not automatically reconnect after connection loss.

Quick Fix

Wrong

client.reconnect()  # Must handle reconnect manually

Client stays disconnected — no auto-reconnect logic.

Right

const mqtt = require('mqtt')

const client = mqtt.connect('mqtt://broker:1883', {
  reconnectPeriod: 5000,  // Try every 5 seconds
  connectTimeout: 10000,
  clean: false  // Persist session
})

client.on('connect', () => {
  console.log('Connected')
  // Re-subscribe if clean = true
  client.subscribe('sensors/#')
})

client.on('reconnect', () => {
  console.log('Attempting reconnect...')
})

client.on('close', () => {
  console.log('Closed - reconnect will trigger automatically')
})

Client automatically reconnects every 5 seconds after disconnect.

Prevention

Most MQTT client libraries have built-in auto-reconnect. Configure reconnectPeriod (default: 1s on some, 10s on others). Use exponential backoff for production. Keep Clean Session = false for subscription persistence. Re-subscribe on reconnect if using Clean Session.

DodaTech engineers apply these same patterns across Doda Browser, DodaZIP, and Durga Antivirus Pro for production IoT reliability.

FAQ