Sustaining participatory digital infrastructures in the cultural heritage sector requires integrated policy frameworks, stable governance mechanisms, and interoperable technical systems that empower both institutions and citizens. This paper presents the Croatian Ministry of Culture and Media’s digital infrastructure centered on the national public portal eKultura as a model for long-term, participatory, and standards-driven cultural heritage management. The development of this infrastructure has enabled the establishment of national-level standards, policies, and procedures that guide cultural institutions in digitising their collections and publishing digital content in the central system and on the public portal. By situating the model within broader discussions on participatory infrastructures and governance, it examines how national policies foster transparent decision-making, inclusive participation, and sustainable digital systems.

Since the early 2020s, the Ministry has developed strategic instruments aimed at strengthening systemic capacity for digitisation, data harmonisation, and open access. The Digitisation Plan for Cultural Heritage 2020–2025 established the first fully coordinated national roadmap, setting priorities for digitisation activities across archives, libraries, museums, galleries, and other institutions. It defined methodological standards, promoted cross-sectoral coordination, and ensured alignment with national and international best practices. Building on this foundation, the infrastructure expands the strategic horizon by embedding inclusivity, interoperability, participatory governance, and user-centric design as core principles. The infrastructure emphasizes not only technical standards but also long-term capacity-building, open-data principles, and mechanisms that enable cultural heritage communities to engage meaningfully with digital content. It is aligned with emerging European strategies and recommendations for the Common European Data Space for Cultural Heritage.

At the operational level, the Ministry maintains the eKultura infrastructure, a national digital ecosystem designed to support the creation, management, aggregation, and public dissemination of cultural heritage data. The public portal serves as a central point of access, enabling users to explore digital objects, metadata, collections, and narratives from a wide range of cultural institutions. The infrastructure is supported by extensive governance and technical documentation that standardizes workflows and ensures institutional participation. These materials include national Guidelines for the Digitisation of Cultural Heritage, prescribing standards for imaging, documentation, preservation metadata, accessibility formats, and quality assurance. Detailed user manuals cover metadata entry, object management, validation processes, authority control, and publication workflows, complemented by instructions for central administration, portal management, and specialized guidance for transferring complex digital assets and for making virtual exhibitions on the portal.

The Ministry continuously updates legislation to reflect digital needs, incorporating digitisation requirements into laws governing museums, libraries, and archives. Institutions are required to submit annual digitisation plans, ensuring alignment with national priorities and strategic objectives. The Croatian eKultura framework demonstrates that sustainable participatory infrastructures rely not only on technological innovation but also on governance models that encourage openness, collaboration, and the active involvement of diverse cultural heritage stakeholders. By combining strategic planning, standardized practices, and inclusive participation, the framework exemplifies a scalable, resilient, and user-centered approach to digital cultural heritage management.