Pathway 2: Publishing interoperability solutions via the Interoperable Europe Portal or connected portals, catalogues, and repositories (Article 4(3))
This pathway applies when:
- the sharing entity decides to fulfil Article 4(1) by publishing content;
- the sharing entity proactively publishes content to enable reuse at scale;
- an adapted interoperability solution must be made public in the same way because the upstream solution was made public under Article 4(3).
Publication can be on:
- the Interoperable Europe Portal;
- a portal, catalogue or repository connected to the Interoperable Europe Portal.
Operational publication requirements, metadata fields, onboarding processes, and other Portal-specific implementation details may evolve over time and should therefore always be checked against the current guidance and specifications available on the Interoperable Europe Portal.
Legal basis
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Fulfilment by publication: The obligation in Article 4(1) may be fulfilled by publishing the relevant content on the Interoperable Europe Portal or a connected portal/catalogue/repository (Article 4(3)).
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Effect on reuse conditions: Where the obligation is fulfilled by publication under Article 4(3), Article 4(2) does not apply to the sharing entity (Article 4(3)).
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Commission publication upon request: At the request of the sharing entity, the Commission must publish the relevant content on the Interoperable Europe Portal (Article 4(3)).
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Portal conformance criteria: Solutions accessible through the Interoperable Europe Portal must:
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not be subject to third-party rights preventing distribution and use;
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not contain personal data or confidential information;
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have a high level of alignment with Interoperable Europe solutions (alignment may be proven by publishing the interoperability assessment outcome);
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use a licence allowing reuse at least by other Union entities or public sector bodies, or be issued as open source;
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be regularly maintained under the responsibility of the owner (Article 8(3)(a) to (e)).
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Publication of adapted solutions: If an interoperability solution was made public pursuant to Article 4(3), an adapted interoperability solution shall be made public in the same way (Article 4(4)).
Implementation guidance
🧭 Step 1. Confirm that publication is the appropriate route
Publication is the appropriate route when broad discoverability and reuse are envisioned. It may be particularly suitable when:
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more than one public organisation is expected to reuse the solution;
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similar requests are likely to recur;
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the solution is sufficiently stable and documented to be made publicly accessible;
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the public organisation can keep the relevant reference information, links, ownership or contact details, and lifecycle status accurate over time;
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the solution can meet the conditions for conformance with the Interoperable Europe Portal.
At this stage, the sharing entity should choose between direct publication on the Interoperable Europe Portal (including publication by the Commission at the public organisation’s request) and publication via an existing portal, catalogue or repository.
As both options are valid, the choice may be guided by practical considerations, such as the organisation’s ability to retain ownership and responsibility for the published content, its capacity to update and maintain information over time, and the stability of links and identifiers used.
If publication is not operationally suitable, the public organisation may consider the direct-sharing instead described in Pathway 3.
For open source software solutions, publication through the EU OSS Catalogue may, where relevant operational conditions are met, provide a practical route. For the purposes of these Guidelines, this forms part of the Interoperable Europe Portal ecosystem and is not a separate legal route.
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Output of this step: a route decision, identifying the chosen publication location. |
🛡️ Step 2. Run the Portal-readiness check
Before publication is initiated, the sharing entity may verify that:
- documentation, examples, or sample configurations do not include personal data or confidential information;
- sensitive information is removed;
- licences and third‑party components allow distribution and reuse.
If one or more of the conditions for publication cannot be met, the sharing entity should not use the publication route to fulfil its obligation under Article 4(1). It may instead use direct sharing (described in Pathway 3) under Articles 4(1) and 4(2), or adjust the package so that it can lawfully be made accessible through the Interoperable Europe Portal.
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Output of this step: a completed Portal‑readiness check, retained by the sharing entity as part of its publication record. |
📦 Step 3. Prepare the publication package
The publication package should be proportionate to the nature and complexity of the solution and sufficient to make publication effective.
Because Article 4(2) governs direct, bilateral sharing on request and does not apply where reuse is enabled through publication under Article 4(3), the public organisation should not frame the publication package around Article 4(2) reuse conditions.
The reuse conditions may be included as descriptive information on a voluntary basis.
Early‑stage or still-evolving interoperability solutions may also be published where this supports transparency, discoverability, or collaboration, provided that the scope and maturity of the solution are made clear and that Article 8(3) conditions are met.
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Output of this step: a publication package associated, where applicable, with a defined version or release. |
🌐 Step 4. Option A. Publish directly on the Interoperable Europe Portal, or request Commission publication
When publishing an interoperability solution, the sharing entity may need to provide the descriptive information required by the Interoperable Europe Portal to support search, discovery, and understanding by users.
Whether the sharing entity requests the Commission or directly publishes the solution on the Interoperable Europe Portal, it should provide a complete and coherent publication package. The Commission supports publication, while accuracy and maintenance remain the sharing entity’s responsibility.
Depending on the current interface, the Portal workflow may require descriptive information to support search, discovery and understanding by users.
- the solution title and description;
- the solution classification;
- the solution type;
- the domain;
- the language availability;
- the solution owner and contact information.
These fields are defined by the Portal as part of its operation and do not constitute legally mandated metadata standards under the Act. The sharing entity may also indicate the country of origin and known reuse cases.
The level of detail provided is recommended to be proportionate but complete enough to support discoverability.
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Output of this step: a published entry on the Interoperable Europe Portal, or a formal publication request submitted to the Commission, supported by the necessary materials. |
In focus
The Interoperable Europe Portal provides support resources and guidance to assist public administrations and solution owners in familiarising themselves with the Portal publication process. These resources, available on the Portal’s Solutions page, cover key aspects such as roles and responsibilities of solution owners, eligibility criteria, and How-To articles with practical guidance on how to publish solutions. In addition, the Portal team regularly hosts webinars to provide support to users.
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Metadata models and technical implementation: The Interoperable Europe Portal internally relies on structured information models to organise and present solutions. In practice, this includes the use of models such as the Asset Description Metadata Schema Application Profile (ADMS-AP). The Portal also supports machine-readable access to certain information through a SPARQL endpoint. For software solutions linked in the EU OSS Catalogue, alignment with publiccode.yml specifications is used. |
🔗 Step 4 Option B. If publishing on a connected repository, make sure the ‘connection’ is real and sustainable
This route should be treated as connected only where a stable and maintainable operational arrangement ensures access through the Interoperable Europe Portal; mere public availability of a repository does not constitute connected publication. The sharing entity may consider the following elements:
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stable landing page: a long-lived URL for the solution, linking to individual versions or releases;
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persistent identifiers and versioning: clear identifiers and version tags to allow precise references;
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predictable update mechanism: a transparent approach to update releases or maintaining a change log;
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operation of external catalogues or repositories: if the sharing entity itself operates the external portal, catalogue or repository, it should follow the logic of Article 8(4) by applying necessary and proportionate measures to ensure interoperability with the Interoperable Europe Portal. Technical details of portal-to-portal interoperability are covered in Pathway 6.
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Output of this step: a stable landing page for the interoperability solution; and a minimal connection plan, describing who is responsible for updates and how broken links or outdated references are avoided. |
🔄 Step 5. Maintain the published solution
Where a Portal entry or connected landing page is used, maintenance requires keeping reference information sufficiently accurate to support informed reuse. In many cases, it will be sufficient to keep the Portal entry or connected landing page aligned with that authoritative source in a proportionate manner, so that reusing entities are not misled about the solution’s status.
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Output of this step: a published entry that remains sufficiently up to date over time, with accurate reference information. |
In focus
For further details on this pathway, including legal context, implementation considerations and examples, see the corresponding Section (3.2) in the extended version of the Guidelines.
For further guidance and clarification, please refer to the FAQ section available on the Portal.