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MQTT vs WebSocket: Detailed Comparison, and Implementation Guide

Discover the key differences between MQTT and WebSocket, including performance, security, and scalability. Learn about use cases, and follow step-by-step guides with code examples.


In today's interconnected world, choosing the right communication protocol is crucial for building efficient and scalable applications. Two prominent protocols often compared are MQTT and WebSocket. MQTT (Message Queuing Telemetry Transport) is a lightweight messaging protocol widely used in the Internet of Things (IoT) for its low bandwidth usage and reliable message delivery.
On the other hand, WebSocket is a protocol providing full-duplex communication channels over a single TCP connection, ideal for real-time web applications. This article delves into the differences between MQTT and WebSocket, offering a detailed comparison, use case scenarios, and a step-by-step implementation guide to help developers make informed decisions.

What is MQTT?

MQTT, or Message Queuing Telemetry Transport, is a lightweight messaging protocol designed for low-bandwidth, high-latency networks. Developed by IBM in the late 1990s, MQTT is now an OASIS standard. Its primary features include a publish/subscribe model, low overhead, and efficient use of network resources, making it ideal for Internet of Things (IoT) applications where devices need to communicate frequently and reliably. MQTT supports Quality of Service (QoS) levels to ensure message delivery, and its small footprint makes it suitable for resource-constrained devices.

What is WebSocket?

WebSocket is a protocol that enables full-duplex communication channels over a single TCP connection, allowing for real-time data exchange between a client and a server. Introduced by the IETF as RFC 6455, WebSocket is built on top of the existing HTTP infrastructure, making it easy to implement in web applications.
WebSocket's key features include low latency, efficient data transmission, and support for binary and text data formats. This makes it well-suited for real-time applications such as live chat, online gaming, and financial trading platforms, where instant data updates are critical.

MQTT vs WebSocket: Detailed Comparison

Protocol Structure


Utilizes a broker-based architecture where clients communicate through a central broker. This publish/subscribe model allows for decoupled communication, with clients only needing to connect to the broker to publish or receive messages.


Establishes a direct, persistent connection between the client and server. Once the initial HTTP handshake is completed, the connection remains open, allowing for bidirectional communication without the overhead of HTTP requests.



Designed for minimal bandwidth usage and optimized for low-power devices. It excels in scenarios with intermittent connectivity and high-latency networks.


Offers low-latency communication and is efficient for continuous, real-time data exchange. However, it requires a stable connection and is typically more resource-intensive than MQTT.



Supports SSL/TLS encryption for secure communication. Authentication and authorization can be implemented at the broker level to control access to topics.


Inherits security measures from the underlying HTTP/HTTPS protocols, including SSL/TLS. Additional security can be managed through custom authentication mechanisms at the application level.



Scales efficiently in IoT deployments with numerous devices. Brokers can handle large numbers of connections and manage message distribution effectively.


Suitable for applications with a moderate number of persistent connections. Scalability can be a challenge for very large deployments due to resource constraints on maintaining open connections.

Use Case Scenarios

IoT Applications: Why MQTT is Preferred?

MQTT is highly favored in IoT environments due to its lightweight nature and efficient use of network resources. It is ideal for scenarios where devices have limited processing power and need to transmit data over unreliable networks. Common use cases include smart home devices, industrial automation, and remote monitoring systems, where MQTT's low overhead and reliable message delivery are critical.

Real-time Web Applications: Why WebSocket is Preferred?

WebSocket is the go-to protocol for web applications that require real-time interaction. Its ability to maintain an open, bidirectional communication channel makes it perfect for applications like live chat, online gaming, and real-time data dashboards. The protocol's low latency and support for both binary and text data allow for seamless user experiences in scenarios where instant data updates are essential.

Examples of Applications Using MQTT and WebSocket

  • MQTT: Smart thermostats, fitness trackers, connected cars, and environmental sensors.
  • WebSocket: Live chat applications, multiplayer online games, stock market tickers, and collaborative editing tools.

Step-by-Step Implementation Guide

Step 1: Setting Up the Development Environment

Install the necessary tools and libraries for your chosen programming language. For MQTT, popular libraries include paho-mqtt for Python and MQTT.js for JavaScript. For WebSocket, you might use websockets for Python and the native WebSocket API in JavaScript.

Step 2: Installing Necessary Libraries and Tools



1  pip install paho-mqtt

For WebSocket


1  pip install websockets

Step 3: Writing a Basic MQTT Client

Python Example


1  import paho.mqtt.client as mqtt
3  def on_connect(client, userdata, flags, rc):
4      print("Connected with result code " + str(rc))
5      client.subscribe("test/topic")
7  def on_message(client, userdata, msg):
8      print(msg.topic + " " + str(msg.payload))
10  client = mqtt.Client()
11  client.on_connect = on_connect
12  client.on_message = on_message
14  client.connect("mqtt.eclipseprojects.io", 1883, 60)
15  client.loop_forever()

Step 4: Writing a Basic WebSocket Client

JavaScript Example


1  const socket = new WebSocket('wss://echo.websocket.org');
3  socket.onopen = function (event) {
4      console.log('WebSocket is open now.');
5      socket.send('Hello Server!');
6  };
8  socket.onmessage = function (event) {
9      console.log('Message from server ', event.data);
10  };
12  socket.onclose = function (event) {
13      console.log('WebSocket is closed now.');
14  };
16  socket.onerror = function (error) {
17      console.log('WebSocket Error: ' + error);
18  };

Step 5: Testing the Implementations

  • Run the MQTT client script and ensure it connects to the broker and receives messages.
  • Open the WebSocket client in a browser console and check the connection status and message exchange.

Step 6: Troubleshooting Common Issues

  • MQTT: Ensure the broker address and port are correct. Check network connectivity and firewall settings.
  • WebSocket: Verify the server URL and ensure the server supports WebSocket connections. Check browser console for error messages.

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Code Examples

Basic MQTT Client Code Snippet



1  import paho.mqtt.client as mqtt
3  client = mqtt.Client()
4  client.connect("mqtt.eclipseprojects.io", 1883, 60)
5  client.loop_start()
6  client.publish("test/topic", "Hello MQTT")
7  client.loop_stop()

Basic WebSocket Client Code Snippet



1  const socket = new WebSocket('wss://echo.websocket.org');
3  socket.onopen = function (event) {
4      socket.send('Hello WebSocket!');
5  };
7  socket.onmessage = function (event) {
8      console.log('Message from server: ', event.data);
9  };
By following this guide, you can implement both MQTT and WebSocket protocols in your projects, ensuring efficient and reliable communication for various applications.


In conclusion, both MQTT and WebSocket offer unique advantages tailored to specific use cases. MQTT's lightweight design and efficient resource usage make it ideal for IoT applications, where low bandwidth and reliable message delivery are crucial. WebSocket, with its full-duplex communication and low latency, excels in real-time web applications requiring instantaneous data exchange.
Understanding the key differences in protocol structure, performance, security, and scalability helps developers choose the right protocol for their specific needs. By following the implementation guides and leveraging the provided code examples, developers can effectively integrate these protocols into their projects.

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