*Result*: Structuring Federated Data Interoperability: A Multi-Level Framework.

*Collaboration between organizations is essential for tackling global challenges, optimizing resources, and developing services. It depends on efficient communication to ensure smooth inter- and intra-organizational interactions. While existing frameworks define how to build and operate services, compatibility barriers persist. In this context, interoperability is crucial in ensuring a shared understanding among partners. However, significant challenges remain, as existing solutions often struggle to address the diverse concerns related to data, services, processes, and business operations. Traditionally, interoperability has relied on integrated and unified solutions with clearly defined requirements. However, emerging technologies are shifting toward a more federated approach, offering greater flexibility, automation, and agility. Yet, this approach remains loosely defined, with ambiguous requirements. This paper introduces a contextualization model that structures federated data interoperability into distinct levels, each representing a different degree of compliance with its definition. The model provides a standardized framework for guiding future implementations of federated data interoperability, focusing on middleware solutions that exchange, process, and synchronize data in collaborations. Furthermore, it addresses technical and conceptual barriers, and provides structured requirements for the concept. Finally, this work evaluates state-of-the-art federated interoperability solutions, positioning them within the defined levels and assessing their capabilities against specified requirements. [ABSTRACT FROM AUTHOR]*