---
title: "MQTT Broker for Connected Products & Smart Hardware | ConnectMQ"
description: "Ship smart hardware without running a broker: standard MQTT for ESP32, nRF, embedded Linux and mobile apps, per-device credentials and secure WebSockets."
url: "https://connectmq.com/connected-products/"
language: "en"
---

Connected Products & Smart Hardware

# MQTT for Connected Products & Smart Hardware

If you build smart hardware for your own customers — appliances, wearables, controllers, sensors — your product depends on a broker you should not have to babysit. Focus on the device and the app; let the broker be infrastructure.

[Try it free](https://app.connectmq.com/signup) [Quickstart](https://connectmq.com/developers/)

No card required

What you can build

## Build your connected product on ConnectMQ

You build the firmware and the apps, ConnectMQ moves the data. Every unit you ship publishes its state; your mobile app, support console, analytics and update service each subscribe to the topics they need.

Devices you ship

**ESP32 appliances**products/{id}/state

**Embedded Linux controllers**products/{id}/events

**Wearables via phone**products/{id}/telemetry

**Config & firmware info**products/{id}/config

**ConnectMQ**

-   TLS on 8883
-   per-device ACL
-   secure WebSockets
-   retained messages

What you build on top

**Customer mobile app**

**Support console**

**Product analytics**

**Firmware rollout service**

What you get

## Connected Products & Smart Hardware on ConnectMQ

-   Standard MQTT works with ESP32, nRF, STM32, embedded Linux and mobile apps
-   Browser and mobile apps connect over secure WebSockets
-   Per-device credentials for every unit you ship
-   Same endpoint style from prototype to production
-   Retained config and state, so a device or app that reconnects is up to date at once
-   Last Will tells your app the moment a device goes offline

example topic design

```
products/{device-id}/state
products/{device-id}/events
products/{device-id}/config         (retained)
```

Use cases

## What hardware teams build on ConnectMQ

### Companion mobile app

Customers see live state and control the device from their phone; commands and state travel over the same broker.

### Device provisioning

Each unit gets its own credentials and topic permissions at the factory or on first setup.

### Firmware rollout

Publish an update notice to a device group, watch each unit report its new version and roll out in waves.

### Remote diagnostics

Your support console subscribes to a single unit’s events and logs to help a customer in minutes.

### Usage analytics

Feature usage and errors from the field stream into your analytics, without a separate telemetry stack.

### Pilot batches

Start with a prototype batch on the Free or Basic plan and grow to a large fleet with the same code.

**How a per-device ACL decides**

`Rule for unit-0193: products/0193/#`

| Client | Action | Topic | Result |
| --- | --- | --- | --- |
| unit-0193 | publish | products/0193/state | allowed |
| unit-0193 | subscribe | products/0193/config | allowed |
| unit-0193 | subscribe | products/0194/# | denied |
| unit-0193 | publish | products/0194/commands | denied |
| support-app | subscribe | products/+/events | allowed |

Per-device credentials

## Every unit sees only its own topics

Give each device its own username and password and limit it to products/{its id}/#. A cloned or compromised unit cannot read or control anyone else’s device, and you can revoke one credential without touching the rest of the fleet.

Real-life example

## Your customer taps Boost — the purifier responds in a second

The everyday loop of a connected product: the device in the customer’s home publishes its state, your mobile app subscribes, and commands go back on the device’s own topics. Device and app both connect out to ConnectMQ.

Customer’s living room → ConnectMQ → Your mobile app. Publishes its state when the air gets worse: PM2.5 at 38 µg/m³, fan on level 1. Subscribed to the device’s topics with the customer’s credentials. The customer taps Boost. Speeds the fan up and confirms its new state, which the app shows straight away. Watches the air quality improve — and the device never sees anyone else’s topics.ConnectMQMQTT broker · TLS 8883Air purifierPM2.512383124µg/m³Fan 1Fan 3Boostunit 0193 · 21.5 °CYour mobile appCustomer’s phone · secure WebSockets12383124Customer’s living roomAir purifier · ESP32 · Wi-Fiproducts/0193/state {"pm25":38,"fan":1}products/0193/state {"pm25":38,"fan":1}products/0193/set {"fan":3}products/0193/set {"fan":3}products/0193/state {"fan":3}Your app · nowLiving room: boost on — air improvingCustomer’s living room → ConnectMQ → Your mobile app. Publishes its state when the air gets worse: PM2.5 at 38 µg/m³, fan on level 1. Subscribed to the device’s topics with the customer’s credentials. The customer taps Boost. Speeds the fan up and confirms its new state, which the app shows straight away. Watches the air quality improve — and the device never sees anyone else’s topics.ConnectMQMQTT broker · TLS 8883Air purifierPM2.512383124µg/m³Fan 1Fan 3Boostunit 0193 · 21.5 °CYour mobile appCustomer’s phone · secure WebSockets12383124Customer’s living roomAir purifier · ESP32 · Wi-Fiproducts/0193/state {"pm25":38,"fan":1}products/0193/state {"pm25":38,"fan":1}products/0193/set {"fan":3}products/0193/set {"fan":3}products/0193/state {"fan":3}Your app · nowLiving room: boost on — air improving

1.  19:20 **Air purifier**
    
    Publishes its state when the air gets worse: PM2.5 at 38 µg/m³, fan on level 1.
    
    `products/0193/state → {"pm25":38,"fan":1}`
    
2.  19:20 **Your mobile app**
    
    Subscribed to the device’s topics with the customer’s credentials. The customer taps Boost.
    
    `products/0193/set → {"fan":3}`
    
3.  19:20 **Air purifier**
    
    Speeds the fan up and confirms its new state, which the app shows straight away.
    
    `products/0193/state → {"pm25":31,"fan":3}`
    
4.  19:21 **Customer**
    
    Watches the air quality improve — and the device never sees anyone else’s topics.
    

**Per-device credentials:** unit 0193 may only use `products/0193/#`, so copied firmware cannot read or control anyone else’s purifier.

[ESP32 code sample](https://connectmq.com/code-samples/esp32/) [Swift / Kotlin code sample](https://connectmq.com/code-samples/swift-kotlin/)

Platform

## Features that help with Connected Products & Smart Hardware

[

### Connectivity

MQTT 3.1.1 and 5 over TCP, TLS, WS and WSS

Learn more](https://connectmq.com/connectivity/)[

### Dashboard & monitoring

Live topic cards, signals and ISA-95 workspace

Learn more](https://connectmq.com/monitoring/)[

### Rules & alerts

Threshold rules, alert log and notifications

Learn more](https://connectmq.com/rules-alerts/)

Solutions

## Other ways teams use ConnectMQ

[

### Industrial IoT & Smart Manufacturing

Machines, PLC gateways, OEE and quality data

](https://connectmq.com/industrial-iot/)[

### Smart Home

Hubs, sensors and Home Assistant setups

](https://connectmq.com/smart-home/)[

### Fleet Telematics

Vehicle tracking, telematics and cold chain

](https://connectmq.com/fleet-logistics/)[

### Smart Energy

Meters, EV chargers, solar and batteries

](https://connectmq.com/energy-utilities/)[

### Connected Robots & Physical AI

Robot fleets talking to fleet managers and AI pipelines

](https://connectmq.com/robotics/)[

### Data Center Monitoring

Power, cooling and rack environment

](https://connectmq.com/data-centers/)[

### Smart City

Streetlights, parking, air and waste sensors

](https://connectmq.com/smart-city/)[

### Smart Agriculture

Soil probes, weather stations and irrigation

](https://connectmq.com/smart-agriculture/)[

### Prototyping & Education

From first ESP32 to classroom labs

](https://connectmq.com/prototyping-education/)

Industries & use cases

## Where teams use Connected Products & Smart Hardware

### Industries

-   [Healthcare](https://connectmq.com/industries/healthcare/)
-   [Retail & E-commerce](https://connectmq.com/industries/retail-ecommerce/)
-   [Telecom](https://connectmq.com/industries/telecom/)
-   [Financial Services](https://connectmq.com/industries/financial-services/)

### Use cases

-   [Connected Vehicles](https://connectmq.com/use-cases/connected-vehicles/)
-   [Cold Chain Monitoring](https://connectmq.com/use-cases/cold-chain-monitoring/)
-   [Remote Patient Monitoring](https://connectmq.com/use-cases/remote-patient-monitoring/)
-   [Hospital Equipment Monitoring & Tracking](https://connectmq.com/use-cases/medical-equipment-tracking/)
-   [Real-Time Notifications](https://connectmq.com/use-cases/real-time-notifications/)
-   [Smart Store Operations](https://connectmq.com/use-cases/smart-store-operations/)
-   [ATM & POS Terminal Monitoring](https://connectmq.com/use-cases/atm-pos-terminal-monitoring/)
-   [IoT Platform for Operators](https://connectmq.com/use-cases/iot-platform-for-operators/)
-   [Real-Time Market Data](https://connectmq.com/use-cases/real-time-market-data/)

Pilot

## Prototype your first units this week

Start on the Free plan with no card. Basic covers up to 100 concurrent connections — enough for a prototype batch and your test apps. Move to Scale as shipments grow — same endpoint style, no firmware rewrite.

[Start for free](https://app.connectmq.com/signup) [See pricing](https://connectmq.com/pricing/)

## Articles

[All articles](https://connectmq.com/blog/)

IoT Tutorials

### [ESP32 MQTT Tutorial: Publish Sensor Data and Control an LED with Arduino IDE](https://connectmq.com/blog/esp32-mqtt-tutorial/)

Connect an ESP32 to an MQTT broker with Arduino IDE and PubSubClient, publish JSON temperature readings, control the onboard LED from the command line and upgrade to TLS with portal credentials.

August 23, 20269 min read

Managed MQTT Cloud

### [What Is a Managed MQTT Broker? Benefits, Costs and How to Choose](https://connectmq.com/blog/managed-mqtt-broker/)

A managed MQTT broker lets you run IoT messaging without operating servers, certificates or patches yourself. Compare managed and self-hosted, pick a deployment model and connect your first client in five minutes.

September 1, 202610 min read

MQTT Security

### [MQTT Security Best Practices: A 12-Point Checklist for IoT Teams](https://connectmq.com/blog/mqtt-security-best-practices/)

A hands-on MQTT security checklist covering TLS, credentials, client IDs, topic design, payload validation, rate limits and certificate checks, plus how ConnectMQ handles each point.

September 28, 202611 min read