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Middleware is not a middle layer. It is the safety valve.

Scalable architecture

CONTENT

  • Why this pattern keeps repeating
  • OPC UA and MQTT are not competitors
  • Why this is also a compliance argument
  • The role of Capture

Connecting directly feels fast. No extra component, no extra hop, no latency added by an intermediate step. In a pilot environment with one machine and one dashboard, that is largely true. The problem does not appear at the first connection but at the tenth, when every data source is linked to multiple applications, each through its own protocol and its own logic, and a change in one source system has a cascading effect on everything attached to it.

Why this pattern keeps repeating

The appeal of direct integration is understandable: it delivers results quickly and requires little architectural discussion. But every point-to-point connection is by definition an agreement between exactly two systems, and that agreement is fragile the moment either one changes. Firmware updates, new sensor types, modified data structures in a SCADA system: each of those changes requires adjustments to every connection that depends on it, individually, by someone who knows the original configuration or has to reconstruct it. In more complex production environments, hypothetically 30 to 40 percent of engineering time in integration projects goes to maintaining previously built connections rather than building new functionality.

At some point, the organisation realises it is spending more time keeping connections alive than extracting value from the data flowing through them. That is not a technical failure. It is the predictable consequence of an architectural principle that structurally excludes scalability.

OPC UA and MQTT are not competitors

A broker architecture resolves this structurally, but also requires that OPC UA and MQTT are understood correctly, because they are often confused or presented as alternatives to each other. OPC UA is an information model: it describes what data means, in which context it exists and how assets relate to one another. MQTT is a transport protocol: it ensures that messages travel from producers to consumers in an asynchronous, lightweight way. The broker in the middle is the point where data producers and data consumers are decoupled, and where access, policy and data flow control become centrally manageable.

For the OT engineer, this means his SCADA or PLC maintains just one connection, to the broker, and what happens to the data afterwards does not affect his system. For IT, that same architecture means there is one point where ingress and egress are controlled, with central logging and central governance over who may consume which data streams.

Why this is also a compliance argument

In a context where the Cyber Resilience Act requires data flows to be documentable and controllable, a central broker is not the intermediate step you bypass to move faster. It is the structure that makes that documentability actually deliverable, because there is one manageable point instead of dozens of individual connections each needing to be tracked, documented and secured separately.

Middleware is not the bureaucratic layer you insert because an architecture diagram calls for it. It is the safety valve that ensures connections remain manageable as they grow in number, and that the organisation is not forced to rewrite its integration history when it wants to scale.

The role of Capture

Capture acts as the broker and contextualisation layer that prevents industrial connectivity from turning into a web of fragile dependencies. Instead of linking every data source directly to every application, Capture creates a controlled point where industrial data arrives, is structured, and becomes available to the systems that need it. That broker role matters because it separates producers from consumers: a PLC, SCADA system or machine does not need to know which dashboard, report, workflow app or analytics tool will use its data later.

This is where middleware becomes more than an extra technical component. It becomes the safety valve of the architecture. Capture allows OT teams to keep source systems stable, while IT gains one governable layer for access, logging and data flow control. OPC UA, MQTT, broker architecture and semantic context are not treated as separate technical choices, but as parts of one integration model. The result is a data architecture that can grow without forcing every new use case to disturb what already works.