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MQTT and its Standardising Role in IoT

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MQTT is a standard messaging protocol by OASIS for the IoT. It is lightweight, ideal for remote devices with low code and bandwidth. Used widely in industries like automotive, manufacturing, telecommunications, IoT gateways, oil, and gas.

MQTT Specification:

MQTT is essential in IoT systems as a lightweight message protocol ideal for low-bandwidth, high-latency, or unreliable networks. Its key roles and benefits in IoT systems are:

MQTT (Message Queuing Telemetry Transport) Advantages in IoT systems:

Efficient Data Transmission: 

MQTT is designed to minimize network bandwidth and device resource requirements, making it ideal for connecting remote devices. MQTT is designed to be lightweight and efficient, making it suitable for IoT devices with limited processing power, memory, and bandwidth. It minimizes data transmission overhead, reducing network traffic and conserving device resources.

Reliable Message Delivery: 

MQTT offers different grades of Quality of Service (QoS) for secure message transmission. It backs “at most once,” “at least once,” and “exactly once” delivery assurances, permitting adjustment to diverse network statuses and message importance, ensuring reliable message exchange under varying network conditions.

Flexible Bi-directional Communication: 

MQTT enables not only device-to-server and server-to-device communications but also supports device-to-device messaging through the broker, facilitating complex IoT interactions. It allows devices to publish messages to a broker and subscribe to topics of interest. This flexibility enables complex interactions and coordination between devices, servers, and applications in an IoT system.


MQTT’s publish-subscribe model and lightweight nature make it highly scalable. It can handle a large number of devices and messages, making it suitable for both small-scale deployments and massive IoT ecosystems with millions of devices. Its lightweight nature and use of a broker-based (publish-subscribe) model allow MQTT to scale well from a few devices to millions, making it suitable for both small and large IoT deployments.

Low Latency: 

MQTT’s efficient protocol design and lightweight message header result in low latency communication. It enables near real-time data exchange, making it suitable for time-sensitive applications in IoT, such as monitoring, control, and automation


MQTT supports secure communication through TLS/SSL encryption, ensuring data privacy and integrity. It provides authentication and access control mechanisms, protecting IoT systems from unauthorized access and data breaches.

Energy and Battery Efficiency: 

MQTT’s lightweight design and efficient message transfer reduce power consumption, making it suitable for battery-operated IoT devices. This feature is essential for IoT deployments where devices are often constrained by limited battery life.

Reliability on Unreliable Networks: 

MQTT is designed to operate in unreliable networks with limited bandwidth and high latency. It can handle network disruptions and intermittent connectivity, ensuring message delivery even in challenging network conditions.

Real-time Communication: 

MQTT’s low latency message delivery is ideal for real-time IoT applications, such as monitoring and controlling devices in smart homes, industrial automation, and more.

In summary, MQTT facilitates efficient, reliable, and secure data exchange between IoT devices and the server, making it a cornerstone for building responsive, scalable, and robust IoT ecosystems. By leveraging these advantages, MQTT empowers IoT systems with efficient, reliable, scalable, and secure communication, enabling seamless connectivity and interoperability between devices, applications, and services.

MQTT Quality of Service Parameters

MQTT ensures reliable message delivery in challenging network conditions using Quality of Service (QoS) levels. MQTT supports three levels of QoS:

QoS 0 (At Most Once): 

In this level, the message is delivered once, and no acknowledgment or retransmission is performed. This level provides the lowest reliability but the highest efficiency. The message is sent and forgotten, without any guarantee of delivery.

QoS 1 (At Least Once): 

With QoS 1, the message is guaranteed to be delivered at least once. The sender will attempt to deliver the message, and the recipient will send an acknowledgment (PUBACK) to confirm the receipt. If the sender does not receive the acknowledgment, it will resend the message. This level ensures reliable message delivery but can result in duplicate messages in case of network disruptions.

QoS 2 (Exactly Once): 

QoS 2 offers highest reliability, ensuring that messages are delivered precisely once through a two-step handshake process. The sender sends a message, the recipient acknowledges with PUBREC, the sender confirms with PUBREL, and the recipient responds with PUBCOMP. While this level guarantees no duplicate or lost messages, it results in increased network overhead and latency.

By allowing different QoS levels, MQTT allows applications to choose the appropriate level of reliability based on the specific requirements of the IoT system. The QoS levels enable MQTT to adapt to challenging network conditions, such as intermittent connectivity, high latency, and network disruptions. The sender and receiver can negotiate and ensure the desired level of message delivery guarantee, providing robust and reliable communication in IoT systems.

Conclusion: What are the Main Roles of MQTT?

In conclusion, MQTT plays a crucial role in enabling efficient and reliable communication between IoT devices. Its lightweight protocol and publish/subscribe model make it an ideal choice for transmitting data in real-time, making it widely used in industries such as healthcare, transportation, industrial uses, and smart home technology. Additionally, MQTT’s ability to support low-bandwidth and unreliable networks makes it highly adaptable for various use cases. Overall, MQTT serves as a vital tool in facilitating seamless communication between connected devices, ensuring the smooth operation of IoT systems at scale.

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