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OPC UA vs. MQTT

OPC UA (Unified Architecture) and MQTT (Message Queue Telemetry Transport) are industrial internet of things (IIoT) and Industry 4.0 communication technologies. In terms of functionality and use cases, they have certain commonalities but also considerable variances.

OPC UA is a platform-independent, service-oriented protocol that enables data interchange between devices and applications securely and reliably. It is frequently employed in manufacturing and process control systems, building automation, and smart grid applications. OPC UA is built on a client-server architecture, in which a client device asks for data from a server device, which then answers with the desired data. OPC UA also allows clients to subscribe to a server’s data and get real-time changes.

On the other hand, MQTT is a lightweight publish-subscribe protocol frequently used on networks with low bandwidth and high latency. It is intended for usage in devices with limited resources, such as sensors and actuators, and is frequently employed in industrial automation, home automation, and other Internet of Things applications. MQTT is based on a broker-client architecture, in which a broker functions as the central server, and clients connect to publish or subscribe to data.

One of the primary distinctions between OPC UA and MQTT is their respective security levels. OPC UA is regarded as more secure than MQTT since it allows encrypted communication and digital certificates. MQTT, on the other hand, relies on an external security mechanism to offer security.

A further distinction is the degree of adaptability and scalability. OPC UA is more adaptable and scalable than MQTT because it supports a wider variety of data types and a more robust data architecture. OPC UA also permits the building of custom data models and can manage more complicated data structures. MQTT, on the other hand, focuses more on transmitting tiny messages and is less flexible when processing complicated data structures.

OPC UA is often utilized in industrial and process control systems, as well as building automation and smart grid applications. It is also utilized in industrial automation for real-time monitoring and control of equipment. In contrast, MQTT is frequently utilized in IoT applications such as home automation, industrial automation, and other low-bandwidth, high-latency networks.

In conclusion, OPC UA and MQTT are both IIoT and Industry 4.0-compatible communication technologies. Both have their own advantages and disadvantages, and the choice of which one will rely on the unique application needs. OPC UA is more secure, adaptable, and scalable than MQTT, but MQTT is more suited for IoT applications because it focuses on conveying short messages.


There are significant differences between the OPC UA and MQTT protocols:

  • OPC UA is a protocol for industrial automation, whereas MQTT is a lightweight protocol designed for use in devices and networks with limited resources.
  • OPC UA is a more comprehensive protocol that can handle various data types and communication patterns, whereas MQTT is a simpler protocol used primarily for publish/subscribe messaging.
  • OPC UA is built with security features such as encryption and authentication, whereas MQTT relies on the security of the underlying transport layer.
  • MQTT is more commonly used in the Internet of Things (IoT) to enable communication between devices and cloud services, whereas OPC UA is typically employed in industrial settings.