WebSocket’s Competition: MQTT vs. WebRTC Protocols

MQTT is a simple messaging protocol designed for devices that have limited power or memory, and work in areas with slow or unstable internet connections. It’s built to handle situations where messages might be delayed or not arrive at all.

At the core of MQTT are topics and subscriptions. Topics are like channels, organized in a tree-like structure with parts separated by slashes. For example: “Myhome/livingroom/light1”.

When a device subscribes to a certain topic, it lets the central MQTT broker (server) know that it wants to receive messages sent to that topic. The server then keeps track of that request and sends any new messages to the subscribed device.

Another key part of MQTT is Quality of Service (QoS), which ensures messages get through even when the connection is not perfect. It has three QoS levels, allowing it to suit different needs depending on the use case and tools for automatic reconnection when a device loses connection.

WebRTC and MQTT differ significantly in their intended purpose, transport mechanisms, messaging patterns, and typical application scenarios. A comparative analysis across these dimensions highlights their distinct strengths and weaknesses for different use cases.

WebRTC is used in various industries for real-time communication, including video conferencing, file sharing, and live streaming. Some of the big products using WebRTC include:

• Google Meet: Utilizes WebRTC for direct peer-to-peer audio and video communication.
• Zoom: Employs WebRTC mainly for meetings accessed through web browsers.
• Facebook Messenger: Leverages WebRTC to enable real-time voice and video calling.
• Discord: A platform popular among gamers, Discord uses WebRTC for live voice and video interactions.
• Airbnb: Implements WebRTC in its online experiences feature to allow live user interactions.

In contrast, MQTT uses a lightweight publish/subscribe model, making it the preferred choice for IoT device communication. A wide range of everyday devices, such as thermostats, appliances, or security systems, as well as wearable devices like smartwatches, fitness trackers, health monitoring tools, or even our smartphones, can be connected using MQTT.

MQTT is used not only because it’s a widely adopted standard, but it also provides real performance benefits, for consumer and IoT business applications, where minimizing bandwidth consumption and maximizing battery life are critical for delivering seamless user experience.

MQTT has become a foundational technology across a wide range of industries, such as:

• Facebook Messenger: the team at Facebook chose MQTT over HTTP because mobile applications are fairly like IoT workloads in regard to network connectivity and the necessity to reduce battery usage. For group chats in Facebook Messenger, MQTT’s publish/subscribe model worked well because each group chat could act as its own topic, allowing users to join and send or receive messages.
• Instagram: Uses MQTT for delivering push notifications and other features.
• Automotive: BMW, for example, built their car-sharing service that manages a fleet of over 14,000 vehicles across 18 cities on top of MQTT
• Asset Tracking & Logistics: MQTT is ideal for real-time monitoring of assets as they move all around the world. In the event of connectivity loss during transmission, MQTT’s protocol ensures that data is reliably delivered once the network connection is re-established.
• Smart Cities are using more IoT technology to work better and be more eco-friendly. The IoT in Smart Cities market was valued at about $182.07 billion in 2024 and is expected to grow to $214.11 billion in 2025, with a compound annual growth rate of 17.12%, reaching $469.96 billion by 2030. MQTT serves as the main communication language for these devices.

To get started more quickly with WebRTC, several helpful libraries are available:

• Socket.io – Great for managing connections
• Simple Peer – Makes WebRTC easier to use
• Twilio Programmable Video – Offers more features and helps your app handle more users

Among these, SimplePeer stands out for its simplicity and ease of use. It’s an open-source library with an MIT license and is actively maintained. It also comes with clear documentation and a few easy-to-follow examples, making it an excellent choice for developers new to WebRTC.

Setting it up is straightforward and involves just a few steps:

1. 1. Install the library in your project
   2. Use a Peer object and create a connection
   3. Start sending video, audio, or binary data

For example:

Twilio offers a more professional solution, offering not just a library, but an entire ecosystem. It provides powerful tools and services for building scalable, production-ready video applications, along with:

• Built-in support for signaling TURN/STUN servers
• Seamless integration with other Twilio services (like SMS, authentication, etc.)
• Rich documentation and SDKs for multiple platforms

Twilio helps abstract away the complexities of managing WebRTC infrastructure, including the tricky parts like NAT traversal and server maintenance. However, it’s a commercial solution, where usage is charged by the minute.

You can find out more information about how to start here: Twilio Video JavaScript Guide.

At the core we have MQTT brokers and MQTT clients.

The senders don’t send the messages directly to recipients, but instead they use an MQTT broker. This way, MQTT clients publish data to the broker, which then distributes it to subscribed clients based on a predefined topic. Each message contains a topic identifier, enabling clients to subscribe to only the topic of interest. The broker keeps a list of subscribers, and based on that list, it sends the messages to the appropriate clients.

There are many open-source MQTT clients available covering many programming languages. HiveMQ offers a great collection of tutorials and examples to help developers get started. Some popular MQTT client libraries include:

• MQTT.js for all the web clients in JavaScript
• PAHO MQTT written in Java
• HiveMQtt – C# MQTT Client for .NET

For a more comprehensive list of MQTT SDKs, please visit this link.

Before proceeding, ensure that you have an MQTT broker to communicate and test with. There are several options for obtaining an MQTT broker:

1. 1. Private deployment using Docker using one of the docker images from EMQX
   2. Fully managed cloud paid service
      • AWS offers a couple of brokers: Mqtt-broker-moquette
      • Azure offers Azure Event Grid for use with mqtt
      • EMQX Serverless
   3. Free public MQTT broker with no credit required (https://www.hivemq.com/company/get-hivemq/)

After we have the broker, we can create the clients that are going to be connected to it.

Let’s use the MQTT.js library, which can be installed easily by running the `npm install mqtt` command. Then we create the client instance:

import mqtt from 'mqtt';
const client = mqtt.connect('mqtt://broker.com');

.

The role of a broker is to relay the messages to the clients, using one connection for each client. Every device only needs to open one connection with a broker to share data with numerous other devices. For instance, HiveMQ’s MQTT broker can support up to 200 million connections.

We first need to use authentication to have access to our broker, so let’s change the code a bit:

import mqtt from 'mqtt';
const client = mqtt.connect('mqtt://hostname', {
    username: 'username',
    password: 'password'
});

.

And now let’s send the classical Hello World with MQTT.

client.publish('netrom/craiova/sensors/lightbulb', 'Hello World!');

.

We can subscribe to MQTT messages using the subscribe method:

client.subscribe('netrom/craiova/sensors/lightbulb');

.

Now you have created a very basic implementation. Obviously before deploying to production, we would still need to secure it a bit better with HTTPS because MQTT is designed to share data between IoT devices as efficiently as possible, not as securely as possible. A full example can be found at ultimate-guide-on-how-to-use-mqtt-with-node-js.

There isn’t a clear “winner” between WebRTC and MQTT because both technologies have a very specific role in the ecosystem. And a lot of big companies, like Facebook Messenger, can decide to use both: MQTT for signaling and message delivery and WebRTC for video, audio and file sharing.

The choice between using WebRTC or MQTT (or both) should be based on a clear understanding of the application requirements. If you’re building a chat application or a platform for sharing files, the right choice is clear WebRTC due to its peer-to-peer architecture and low-latency communication. But if you intend to use it to communicate with other low power devices or unreliable networks, MQTT is often the better choice, especially in IoT environments.

In the end, it’s not about choosing one over the other as these technologies aren’t competitors. When combined, both can support highly responsive, scalable and efficient real-time solutions.