The European Open Science Cloud (EOSC) entered its second formal phase at the start of 2026 with a substantially revised governance and funding model. The transition from the EOSC Association-led implementation phase (2021-2025) to the EOSC Federation operating model (2026 onwards) is the most significant infrastructure-governance change in EU open science since the FAIR principles were articulated. This post walks through what changed, who is affected, and how integrators should reposition.
What EOSC was, and what it is becoming
EOSC was conceived in 2016 as a federated cloud-based infrastructure providing researchers across the EU and associated countries with access to data, services, and computing for open science. The 2018 implementation phase, the 2021 launch of the EOSC Association, and the cascade of EU-funded projects (EOSC Future, EOSC-Pillar, FAIRsFAIR, EOSC Synergy, and many others) built out the technical layer: the EOSC Portal, the EOSC Marketplace, the AAI federation, the metadata aggregation via OpenAIRE, the persistent-identifier infrastructure connections.
The challenge that has dogged EOSC since its inception is the gap between the technical layer and the operational sustainability layer. EU project funding built impressive infrastructure on time-limited grant terms; what happens after the grants run out has been the open question. The 2024-2025 EOSC strategic review concluded that the project-grant model was not sustainable and that EOSC needed a federated operating model funded by recurring contributions from member states and associated members.
The federation model
The 2026 EOSC Federation is structured as a tiered membership organisation. Core nodes are member-state-designated infrastructures providing strategic services (data repositories of national scale, compute infrastructure, identity providers, metadata aggregators). Core-node operation is co-funded by the home member state and by EOSC central funds; the criteria for core-node status include FAIR data implementation, sustainability commitments, and federation-API conformance.
Federated nodes are participating infrastructures meeting a lighter set of conformance criteria; they integrate with the EOSC federation via documented APIs and contribute to the federated graph but are not core-funded. Most existing EOSC-listed services move into federated-node status by default.
Affiliated services are third-party infrastructures (commercial cloud providers, international partners, non-EU regional clouds) that participate via specific agreements without being members of the federation governance.
The governance structure has three tiers: a Strategic Council of member-state representatives setting policy; an Operational Board of core-node operators making day-to-day decisions; a Stakeholder Forum of federated nodes, researchers, and user-community representatives providing input.
What changed for technical integrators
Three concrete changes matter for technical integrators. First, the EOSC Interoperability Framework v2 ships with the federation launch. It refines the v1 framework with tightened metadata-quality requirements, mandatory ROR organisational IDs for service providers, and standardised provenance metadata for data-services interactions. The CASRAI EOSC IF entry has been updated.
Second, the EOSC AAI consolidation moves the federation onto a unified authentication-and-authorisation infrastructure based on EduGAIN, MyAccessID, and ORCID. The previous federation of identity providers (with several parallel AAI implementations across projects) is being merged. Service providers integrating with EOSC need to support the consolidated AAI; legacy integrations have a 24-month transition window.
Third, the persistent-identifier requirements have been tightened. Core-node services must issue or accept persistent identifiers (DOI, Handle, ORCID, ROR, RAiD as appropriate) for all federated artefacts; metadata records without PIDs are no longer ingested into the EOSC Graph. This brings EOSC into line with what OpenAIRE Graph has long been recommending; in practice many services already comply.
What changed for researchers
The visible changes for researchers are modest in 2026 and will accumulate through 2027-2028. The EOSC Portal remains the primary discovery surface; the EOSC Marketplace continues to list services with the new conformance tiers visible. The single sign-on becomes more reliable as the AAI consolidation reduces the friction across services.
The deeper change is in the funder-mandate side. Several Horizon Europe calls in 2026 require EOSC-conformant data deposit (deposit in a core-node or federated-node repository, with FAIR metadata, with PID assignment). This raises the floor: research data from these projects must land somewhere that is part of the EOSC federation, with all the metadata-quality implications. The CASRAI institutional EOSC guide walks through the deposit options by discipline.
The sustainability question
The federation’s financial model is its hardest unresolved problem. Member-state contributions, EU central funding, and a small fee component from affiliated services are the three pillars. The 2026 budget is set; the 2027 and beyond budgets depend on the Multiannual Financial Framework negotiations that will roll through 2026 and 2027.
The risk to the federation is a return to project-grant precarity: if member-state contributions falter, core-node operations become dependent on rolling EU-project funding again, and the long-term sustainability gain is illusory. The EOSC Association has been clear that member-state buy-in is the critical lever; the institutions and researchers who use EOSC infrastructure should be engaging their national funder representatives on the federation contribution case.
What integrators should do in 2026
For repository managers, the immediate priorities are: verify your service’s status (core node, federated node, affiliated, none); align your metadata to EOSC IF v2; ensure PID assignment is complete for federated artefacts; migrate to the consolidated AAI within the 24-month window.
For institutional CRIS systems and CRIS vendors, the priorities are: ingest EOSC-Portal service metadata into the CRIS service-catalogue layer; support EOSC-conformant deposit workflows from the CRIS to federated repositories; surface EOSC-mandate compliance in the CRIS reporting layer. The CASRAI CRIS integration guide has been updated.
For publishers, the touchpoint is data-availability and code-availability metadata. A paper depositing supporting data in an EOSC federated repository should declare so in its metadata; the EOSC Graph then ingests the linkage. Publishers should be updating their submission systems to capture EOSC-repository deposit identifiers.
The international dimension
EOSC has always sat in relation to the broader international open-science infrastructure: the African Open Science Platform, the LA Referencia network in Latin America, OpenAIRE-Nexus, the Asia-Pacific GRDi work. The federation governance explicitly includes a framework for international affiliation, and several non-EU national infrastructures have begun affiliation discussions. The medium-term direction — five to ten years out — is a loosely federated international open-science cloud with EOSC as one of several regional implementations.
For institutions outside the EU but with significant EU collaboration, the practical implication is that EOSC conformance is becoming a useful target even where it is not mandated. Aligning with EOSC IF v2 and the related FAIR-data infrastructure makes EU collaboration smoother and positions for the broader international federation as it emerges.
