What is MQTT?

The Internet of Things (IoT) and Machine-to-Machine (M2M) communication have transformed how we interact with technology. With the number of connected IoT devices increasing every day, a messaging protocol that enables real-time, reliable, and efficient communication between devices and cloud-based processing systems is critical.

This is where MQTT (Message Queuing Telemetry Transport) plays a central role. Known for its lightweight and scalable design, MQTT has emerged as the de facto standard for IoT and M2M communication. In this blog post, we’ll dive into what MQTT is, how it works, its advantages, and how it’s used across industries – alongside how KORE supports MQTT as part of its global IoT enablement platform.

What is MQTT and what is its history?

MQTT is a lightweight messaging protocol optimized for networks with limited bandwidth and resource-constrained devices. It’s based on a publish-subscribe architecture, which is ideal for IoT environments that require low power usage and efficient data transmission. MQTT is widely used in industries such as automotive, healthcare, manufacturing, energy, and telecommunications.

As an open OASIS standard and ISO recommendation, MQTT is both vendor-agnostic and broadly supported. Originally developed by IBM, the protocol was referred to as “MQ Telemetry Transport.” Over time, the name was simplified to MQTT, and it no longer stands for any acronym, though the technology remains central to telemetry and messaging.

Instead of traditional message queues, MQTT uses a topic-based messaging structure. Devices (clients) can publish messages to a topic, and other devices that subscribe to that topic receive the messages. Its minimal overhead and simplicity make it ideal for constrained devices transmitting small packets of data.

What are the components of an MQTT architecture?

An MQTT system revolves around two main components: clients and brokers.

• Clients are the endpoints – either publishers or subscribers (or both). They connect to a broker to send or receive data by publishing or subscribing to specific topics.
• Brokers are the intermediaries that manage message routing, storing subscription states, and ensuring messages are delivered appropriately – even when subscribers go offline temporarily.

MQTT brokers can be deployed in the cloud, on-premises, or even in hybrid architectures, and they are built to scale, supporting millions of concurrent connections and high message throughput. Cloud providers like AWS and Azure support MQTT-based services, often integrated with other IoT and analytics tools.

Brokers can also retain messages intended for subscribers who momentarily disconnect, ensuring message delivery once connectivity is restored.

How is MQTT used in IoT?

MQTT’s design makes it especially useful in a wide variety of IoT and Industrial IoT (IIoT) use cases:

• Smart Metering: Ensures accurate, real-time meter data delivery for energy or utility providers, enabling timely billing and analytics.
• Remote Environmental Sensing: Efficiently transmits ambient sensor data from hard-to-reach or low-power field devices.
• Predictive Maintenance: Delivers machine health data reliably from connected equipment to operations teams, reducing downtime and improving asset lifecycle management.
• Billing Systems: Provides reliable messaging for financial systems, reducing the risk of duplicate or dropped messages in invoicing workflows.

Popular MQTT broker implementations include HiveMQ, Eclipse Mosquitto, AWS IoT Core, and Azure IoT Hub.