This deliverable documents the first operational release and architectural design of the GreenInCities Shared Data Platform and Marketplace. To avoid building a platform from scratch, the solution expands Sensative’s commercial, horizontal IoT and data integration platform, Yggio.

The platform is designed to act as the central "plumbing layer" or digital backbone for the project, allowing different city departments, sensors, digital twins, and research partners to share, standardise, and analyze complex environmental datasets.

By incorporating ETSI’s Next Generation Service Interface - Linked Data (NGSI-LD) and FIWARE smart-city standards, this deliverable ensures that all data generated from local pilot interventions—such as microclimates, biodiversity counts, and citizen-sensing reviews—is automatically validated, parsed, and translated into a single, unified database.

Primary Audience:

• Municipal IT Departments and Data Managers

• GreenInCities Consortium Technical Partners

• Pilot Coordinators

Secondary Audience:

• The 112 Climate-Neutral and Smart Cities network

• Developers of third-party Smart City applications

The Data Marketplace prototype was developed through a structured process combining technical engineering and collaborative municipal testing:

• Yggio baseline integration: Adapting Sensative’s established horizontal IoT middleware platform—representing over 100 man-years of development—to support the specific requirements of GreenInCities.

• Consortium requirements ingestion: Gathering data, metadata, and sensor requirements through close collaboration with pilot cities and technical partners.

• D4.1 Data model alignment: Translating the conceptual data taxonomy established in Deliverable D4.1 into the platform’s core kernel and translation layers.

• Deployment & pilot feedback: Launching the initial release on the active project testing server (beta.yggio.net), distributing accounts to partner cities, and collecting user feedback to guide future updates.

The prototype is divided into two primary technical blocks:

• The shared data integration platform (Yggio Backbone): Functions as a vendor- and technology-neutral middleware layer that abstracts heterogeneous protocols (LoRaWAN, NB-IoT, BACnet, MQTT, and Modbus). It validates incoming data against the project's data models and provides strict, fine-grained access control, encrypted communications, and organizational data governance to safeguard data sovereignty.

• The data marketplace user interface (UI): A custom-designed, user-friendly portal comprising three primary screens:

  List Page: Displays all available city datasets, allowing users to quickly search, filter, and sort entries by category, project model, or custom tags.

  Create Data Listing Page: A straightforward guided wizard that allows city planners to document new datasets by inputting required search metadata (name, description, category, and tags) alongside attached images and external repository web links.

  Listing Details Page: Provides a visual presentation of the selected intervention, showcasing its descriptive metadata, and, if authorized, providing access to the raw metrics or external databases (e.g., Smart Citizen Platform).

The implementation of this horizontal data marketplace architecture is designed to drive systemic improvements in how cities manage and share environmental data:

• Disparate environmental, spatial, and social datasets are integrated into a single, cohesive smart-city ecosystem, breaking down historical administrative data silos.

• Technical interoperability is secured by aligning all platform schemas with European NGSI-LD and FIWARE standards, allowing seamless integration with broader European data spaces.

• Municipalities gain immediate access to empirical baseline and monitoring data to justify nature-based solutions and calculate clear cost-benefit metrics.

• A scalable, open-source template is established to help follower cities and wider smart-city networks easily replicate and implement secure IoT data-sharing models.

• Figure 1: Data Marketplace List Page

• Figure 2: Create Data Listing Page

• Figure 3: Data Listing Details Page