Summary The proposed Cloud and AI Development Act (CADA) does not mandate that the EuroCloud Federation directly consume specific technical "building blocks" from the Interoperable Europe Act (IEA) as a prerequisite for infrastructure sharing. Instead, CADA establishes the EuroCloud Federation as a voluntary mechanism for public-sector bodies to share cloud and data centre capacity, while simultaneously requiring that public-sector open-source software be published in the EU Open Source Solutions Catalogue (EU OSS Catalogue), which is explicitly hosted on the Interoperable Europe portal. The synergy lies in the broader ecosystem: the Federation facilitates the sharing of sovereign cloud infrastructure, while the Interoperable Europe framework ensures that the software and solutions running on that infrastructure are reusable, discoverable, and interoperable across borders.

Detail

To understand how the EuroCloud Federation interacts with Interoperable Europe building blocks, one must distinguish between the infrastructure-sharing mechanism established by CADA and the software-reuse mechanisms established by the Interoperable Europe Act (Regulation (EU) 2024/903). CADA, as proposed in Regulation COM(2026) 502 final, creates two distinct but complementary pillars for public-sector digital sovereignty: the EuroCloud Federation for infrastructure and the EU Open Source Solutions Catalogue for software.

The EuroCloud Federation: Infrastructure Sharing, Not Software Interoperability

The EuroCloud Federation is established under Article 34 of the CADA proposal. Its primary purpose is to facilitate the sharing of public-sector data centre services and cloud computing services between Union entities and public-sector bodies. Recital 69 clarifies that the Federation aims to bring together national and European cloud initiatives that provide highly trusted and secure public-sector cloud capabilities.

Crucially, the Federation is not a technical platform that ingests "interoperability building blocks" in the sense defined by the Interoperable Europe Act (such as digital identity wallets or cross-border data spaces) as a mandatory technical requirement for entry. Instead, it is a cooperative framework governed by public interest considerations. Article 35 stipulates that sharing within the Federation is free of charge, except for costs strictly necessary to recover additional expenses incurred by the sharing entity. This sharing is anchored in public-sector cooperation and does not constitute a pecuniary interest or public contract under standard procurement rules.

The technical requirements for the Federation are focused on security and resilience rather than software interoperability standards. Article 35(2) requires the sharing entity to implement appropriate technical, operational, and organisational measures to ensure effective, secure, and resilient service provision. This includes policies on risk analysis, information system security, access control, incident handling, business continuity, and interoperability and connectivity. While "interoperability" is mentioned here, it refers to the technical ability of the shared cloud resources to connect and function securely, not to the mandatory adoption of specific Interoperable Europe software building blocks.

The EU OSS Catalogue and the Interoperable Europe Portal

The direct link between CADA and the Interoperable Europe infrastructure is found in Article 43. This article mandates that the Commission provide and maintain an EU Open Source Solutions Catalogue (EU OSS Catalogue). Article 43(2) explicitly states that this catalogue shall be hosted on the Interoperable Europe portal referred to in Article 8 of Regulation (EU) 2024/903 (the Interoperable Europe Act).

This creates a practical dependency for public-sector bodies. Article 42 requires that when Union entities or public-sector bodies make software available for reuse under an open-source licence, they must do so using a catalogue or repository connected to the EU OSS Catalogue. Therefore, the "building blocks" of public-sector innovationβ€”open-source software developed by or for public bodiesβ€”are aggregated in a centralised location hosted on the Interoperable Europe platform.

Synergies: Shared Interoperability Solutions

While the EuroCloud Federation and the EU OSS Catalogue are legally distinct mechanisms under CADA, they function synergistically within the broader EU digital strategy. Recital 83 notes that software is often made available in different repositories, hampering searchability and reuse. By centralising open-source software in the EU OSS Catalogue (hosted on the Interoperable Europe portal), the EU ensures that solutions can be easily linked to further relevant information and training.

For the EuroCloud Federation, this means that the software running on the shared sovereign cloud infrastructure is more likely to be interoperable and reusable. If a public-sector body develops an AI model or cloud-based application using open-source principles, it is encouraged (and in some cases required) to share it via the EU OSS Catalogue. Other members of the EuroCloud Federation can then discover this software, ensuring that the infrastructure sharing is complemented by software interoperability.

Recital 69 also highlights that the Federation should facilitate the sharing of capabilities between Union entities and public-sector bodies. The Interoperable Europe Act's focus on interoperability solutionsβ€”such as common data models, APIs, and digital servicesβ€”provides the technical "glue" that allows diverse national cloud infrastructures within the Federation to operate cohesively. While CADA does not explicitly mandate the use of Interoperable Europe building blocks within the Federation, the broader policy context (including the Digital Decade Policy Programme) encourages the use of interoperable solutions to ensure that shared cloud capacity is effectively utilised for cross-border public services.

Governance and Open Source Programme Offices

To support this ecosystem, Article 44 establishes a network of Open Source Programme Offices (OSPO Network). This network facilitates cooperation on the implementation of open-source obligations, including the sharing and reuse of software. The OSPO Network promotes the exchange of best practices related to licensing, security, maintenance, and procurement of open-source software. This governance structure ensures that the software shared via the EU OSS Catalogue (and potentially used within the EuroCloud Federation) meets high standards of quality and interoperability, aligning with the principles of the Interoperable Europe Act.

What this means for you

For CTOs, architects, and SMEs evaluating the practical impact of CADA, the distinction between infrastructure and software is critical.

  1. For Public-Sector Architects: If you are designing cloud architectures for public-sector bodies, you must prepare for two separate compliance streams. First, ensure that your cloud infrastructure can participate in the EuroCloud Federation by meeting the security and resilience criteria of Article 35. This means implementing robust access controls, incident handling, and interoperability measures that allow for secure sharing of capacity. Second, ensure that any software developed or maintained by the public sector is published in a repository connected to the EU OSS Catalogue (Article 43). This requires adopting open-source licensing and ensuring your code is discoverable via the Interoperable Europe portal.

  2. For SMEs and Cloud Providers: The EuroCloud Federation creates a new market for sovereign cloud services. However, the Federation is limited to public entities (Article 34(1)). Private participation is excluded where the sharing entity owns the hardware (Article 35(1) and Recital 71). Therefore, SMEs cannot directly join the Federation as cloud providers. Instead, they should focus on providing the underlying technology, security tools, and open-source software that enable public-sector bodies to meet the Federation's requirements. Additionally, SMEs developing open-source solutions should publish them in the EU OSS Catalogue to increase visibility and adoption by public-sector bodies within the Federation.

  3. For Interoperability Specialists: The integration of the EU OSS Catalogue into the Interoperable Europe portal means that interoperability standards (such as common data models and API specifications) will be increasingly important for software reuse. Architects should design their open-source solutions to comply with Interoperable Europe standards to ensure they are easily discoverable and reusable by other public-sector bodies within the EuroCloud Federation.

Common misconceptions

  • Misconception: The EuroCloud Federation is a technical platform that automatically integrates Interoperable Europe building blocks.

    • Reality: The EuroCloud Federation is a legal and operational framework for sharing cloud capacity. It does not automatically ingest software building blocks. Interoperability is achieved through the separate mechanism of the EU OSS Catalogue and the adoption of common standards by public-sector bodies.

  • Misconception: Private companies can join the EuroCloud Federation to offer cloud services.

    • Reality: Participation is limited to Union entities and public-sector bodies (Article 34(1)). Private companies can only participate indirectly by providing technology and support services to public-sector members.

  • Misconception: CADA replaces the Interoperable Europe Act for cloud interoperability.

    • Reality: CADA and the Interoperable Europe Act are complementary. CADA focuses on cloud sovereignty and infrastructure sharing, while the Interoperable Europe Act focuses on software and data interoperability. The EU OSS Catalogue, mandated by CADA, is hosted on the Interoperable Europe portal, demonstrating their integration.

Official sources

Related

This is general information about a draft EU regulation, not legal advice.