Open data interfaces pay off for reporting and integration

Data collection is not enough. You do need control. Today, data collection itself is no longer surprising. The real challenge is how to use data afterwards. Not only storing and displaying it, but also providing it to systems that need to process it. The format and openness of data determine whether it will remain usable in the long term.

That is why an open data interface is a key element of modern infrastructure. Unlike proprietary protocols, it allows standardised processing and sharing across applications. The result is greater flexibility, lower vendor lock-in and long-term sustainability.

What an open data interface is and how it works

An open data interface is a standardised way of transmitting and storing data. Thanks to a unified format, it enables efficient processing and the ability to combine data in different applications. Open formats and protocols bring four major benefits: Support across a wide range of tools and libraries, long-term compatibility and backward readability, easy data sharing between users and systems and the possibility to preserve analysis results in a form that remains usable.

Practical examples of open interfaces include API (Application Programming Interface), a structured way to automatically retrieve or send data. MQTT (Message Queuing Telemetry Transport), a lightweight protocol for IoT devices. HTTP(S) Push, an active sending of data to a defined address. CSV export, an universally readable format for Excel and other tools, generated directly in the cloud.

Why cloud-only access is not enough

Cloud services simplify data collection and visualisation, but without an open interface they become a black box. Data is controlled by the provider, not you. If pricing changes or the service is discontinued, you risk losing access or facing a difficult export.

An open interface, by contrast, provides independence. Users can export data, combine it with other sources and use it in their own tools. In practice, this means being able to:

• create customised dashboards and results,
• combine consumption with other data (e.g. production, weather),
• connect company reporting systems (Power BI, Excel, EMS, SAP),
• automate ESG and ISO 50001 reporting,
• integrate data into higher-level systems (BMS, SCADA).

What a quality data interface looks like in practice

To be truly usable, an interface should meet several essential parameters:

Well-documented API

• clear descriptions of query and response structures,
• usage examples, SDK and versioning,
• access to both real-time and historical data.

Secure authentication and encryption

• support for OAuth2, tokens or API keys,
• communication via HTTPS,
• permission management by user or application.

Standard formats and protocols

• JSON, XML, CSV,
• MQTT, HTTP, WebSocket.

Filtering and querying capabilities

• selection by time, data type or device.

Scalability and stability

• ability to handle multiple clients and higher volumes without outages.

Open interfaces are applied across different industries, for example in water utilities, where consumption data combined with meteorological information helps predict network load depending on weather conditions. In district heating meter data flows directly into the SCADA system, supporting boiler operation optimisation and fuel efficiency. In property management sector MQTT transmissions from meters integrated with a BMS system enable immediate reactions to consumption spikes, e.g. automatic load reduction during peak times. Such scenarios clearly show that open interfaces are not just a technical detail, but a tool with a direct impact on efficiency and costs.

Common mistakes in implementation

Despite their advantages, open interfaces are often implemented with recurring mistakes:

• choosing solutions with proprietary protocols that restrict further development,
• insufficient verification of documentation quality and support,
• lack of performance testing with larger data volumes,
• underestimating security and authentication.

Avoiding these mistakes helps protect investments and ensures that the system remains fit for the future.

Think about openness when choosing technology

When purchasing metering equipment or data collection systems, always ask about the availability of open interfaces. Quality documentation, standard protocols and the absence of restrictive licences are decisive factors.

Devices from ACRIOS Systems are built on this openness – converters and gateways with support for MQTT, HTTP(S), REST API, CSV export (processed on the server) and direct integration into building management systems give users the confidence to work with their data completely freely. In the era of digitalisation and energy optimisation, an open data interface is the key to efficiency, sustainability and independence from third parties.