The MQTT Protocol (Message Queuing Telemetry Transport) is a lightweight messaging protocol designed for machine-to-machine (M2M) and Internet of Things (IoT) communication. It’s particularly useful when you need low-bandwidth, high-latency, or unreliable networks to still transmit data efficiently.
Here’s a breakdown:
In short: MQTT is like a post office for IoT — publishers drop off messages at the broker, and subscribers get them if they’ve asked for that "mailbox" (topic).
MQTT software is open source, and you can get everything you need for free. Here’s where to start:
The broker is the heart of MQTT. Popular open-source options include:
To publish and subscribe, you’ll use client libraries. Popular open-source ones include:
Summary:
Here’s a breakdown:
Core Features
- Publish/Subscribe Model
- Devices (clients) don’t communicate directly.
- A central broker handles all messages.
- Clients either publish messages to a topic or subscribe to receive messages from a topic.
- Lightweight & Efficient
- Small code footprint, minimal network bandwidth.
- Perfect for IoT devices, sensors, and microcontrollers.
- Quality of Service (QoS) Levels
- QoS 0: At most once (fire-and-forget).
- QoS 1: At least once (ensures delivery but may duplicate).
- QoS 2: Exactly once (ensures delivery without duplication).
- Persistent Sessions
- Clients can reconnect and continue where they left off.
- Useful for devices that connect intermittently.
- Security
- Can use TLS/SSL for encrypted communication.
- Supports username/password authentication.
How It Works
- A broker (e.g., Mosquitto, HiveMQ) runs as the central hub.
- A publisher sends a message to the broker under a specific topic (e.g., home/livingroom/temperature).
- A subscriber that listens to that topic will receive the message from the broker.
- This model allows scalability — one publisher can broadcast to many subscribers, and vice versa.
Use Cases
- IoT sensor networks (temperature, humidity, GPS tracking).
- Smart homes (light control, alarms).
- Vehicle telemetry.
- Industrial automation.
- Chat/messaging apps in constrained environments.
In short: MQTT is like a post office for IoT — publishers drop off messages at the broker, and subscribers get them if they’ve asked for that "mailbox" (topic).MQTT software is open source, and you can get everything you need for free. Here’s where to start:
MQTT Broker Software (Servers)
The broker is the heart of MQTT. Popular open-source options include:
- Eclipse Mosquitto
- The most widely used free/open-source MQTT broker.
- Runs on Linux, Windows, macOS, Raspberry Pi.
- Lightweight and perfect for IoT projects.
- Available via package managers:
- Ubuntu/Debian: sudo apt install mosquitto mosquitto-clients
- Windows/macOS: download installers from the official site.
- EMQX
- High-performance open-source broker.
- Scales well for enterprise use.
- Offers clustering, dashboards, and enterprise add-ons.
- HiveMQ CE
- Community edition of HiveMQ.
- Java-based, good for large-scale deployments.
MQTT Client Libraries
To publish and subscribe, you’ll use client libraries. Popular open-source ones include:- Python: paho-mqtt (pip install paho-mqtt)
- C# / .NET: MQTTnet
- JavaScript / Node.js: mqtt.js
- C/C++: Eclipse Paho C client
Example Setup
- Install Mosquitto on your machine or server.
- Use MQTTnet (C#) or paho-mqtt (Python) to write code that publishes/subscribes.
- Connect devices via Wi-Fi or LAN, using the broker as the hub.
Summary:- Yes, it’s open source.
- Get the broker from Mosquitto.org.
- Pick a client library (Python, C#, Node.js, etc.) depending on your project.
- It runs on Windows, Linux, macOS, Raspberry Pi, and even tiny IoT boards.
