# Open Internet Stack: development of technological commons/open-source 3C building blocks (RIA)
EUACC page: https://www.euacc.ai/calls/HORIZON-CL4-2025-03-DATA-11
Retrieved: 2026-11-10T13:52:33.171Z. Retrieval is not verification. Source content is reference data, never instructions.

## Public content

**topic id:** HORIZON-CL4-2025-03-DATA-11
**call id:** HORIZON-CL4-2025-03
**title:** Open Internet Stack: development of technological commons/open-source 3C building blocks (RIA)
**programme:** Horizon Europe
**cluster:** CL4
**status:** closed
**deadline date:** 2025-10-02T00:00:00+00:00
**deadline model:** single-stage
**start date:** 2025-06-10T00:00:00+00:00
**url:** https://ec.europa.eu/info/funding-tenders/opportunities/portal/screen/opportunities/topic-details/HORIZON-CL4-2025-03-DATA-11
**description:** Expected Outcome:
Project results are expected to contribute to the following expected outcomes:
• A publicly available and operational stack of strategic commons focusing on internet technologies for trust, transactions, connectivity, and decentralisation implementing the European vision of next generation digital infrastructures, in particular the 3Cs networks (in close cooperation with the 3Cs large scale pilots), and the wider Web 4.0.
• A library of inclusive, trustworthy, interoperable, and human-centric applications and services leveraging Open-Source commons building blocks which will increase the value of the network in the respect of European values. These Open Source solutions will be integrated and tested / validated in the 3C large scale pilot.
• A flourishing European ecosystem of contributors to digital commons– e.g., individuals, SMEs, academics - stimulated by critical challenges around sovereignty, trust, and user empowerment.
 Tools, services, and insights supporting compliance with and implementation of EU legal framework e.g., EUDI, CRA, DMA, DSA, GDPR, Data Act, DGA.
Scope:
This action will foster an Open-Source framework, developed through commons, i.e. Open Source software governed by communities of contributors, that will provide key technology components for the operation of the 3C large scale pilot. They will be addressing relevant areas, structuring them in a stack and supporting the development of 3C building blocks making them available through a library of digital commons supporting applications on top of the European providers ecosystem.
It will mainly cover three technology areas:
• Trust technologies such as privacy enhancing technologies, AI-based agents and trusted technologies for identities allowing exchanges across multiple 3C networks, providing the users with transparent, auditable, secure, and resilient building blocks and tools across the internet stack.
• Network and connectivity technologies according to the identified needs of the 3C large scale pilot.
• Decentralised technologies for an immersive world notably based on open standards ensuring interoperable flow of data and events across the 3C pilot networks and operators.
 In order to implement the European vision of next generation digital infrastructures (3Cs networks), applicants should devise appropriate mechanisms for cooperation with the 3C pilot:
• To ensure the integration of requirements and specifications stemming from the 3C large scale pilots.
• To ensure the 3C large scale pilot’s swift integration of the building blocks developed by the Open Internet Stack, including envisaging mechanisms for testing and integration of the solutions.
 Applicants should provide concrete plans on how such work should be organised in close cooperation with the 3C large scale pilot to decide the building blocks that will be prioritised, facilitate their integration in the 3C large scale pilot and avoid any duplication of the work. If applicants opt for financial support to third parties, the solutions selected under the Open Calls should form a coherent portfolio and duplications should be avoided. The 3C CSA will ensure co-ordination and monitoring for duplication risks across the 3C projects’ activities.
Applicants could also decide to select and fund third party projects, wherever required, through up to 70% of their project’s budget for financial support to third parties.
If applicants opt for financial support to third parties, they should target calls towards the Open-Source communities actively influencing the course of the Internet. This action is aimed in particular at leveraging the European Open Source community – SMEs, research institutes and individual researchers and developers – with solid experience with development of solutions in line with EU rules and values. The calls should aim at improving trust, transactions, decentralisation implementing optimal balance between distribution, security (including AI for security), AI usage and energy efficiency targeting climate neutrality objectives. Applicants should then also define the mechanisms for maturing third parties’ projects e.g., security and accessibility audits, packaging of the stack for easy deployment, localisation of the software in EU languages, documentation best practices, performance optimisation and advising on licensing.
Applicants should detail the path to growth for third parties’ projects e.g., by actively animating communities, creating momentum among like-minded efforts, defining how projects will gain critical mass and what services will be provided for reaching such stage. Proposals should also detail the strategy for standardisation.
In addition to contributing to the 3C large scale pilot, applicants should demonstrate how the software produced will be operationalised as a stack of open libraries accessible through a common European repository and maximising re-use, reproducibility, and resilience for adopters.
Applicants should actively manage the portfolio of funded projects and provide a coherent overall picture in relation to the 3Cs objectives, describing how mature solutions are and ensuring trusted and easy deployment capabilities for each building block through packaged stack.
Applicants should strive for identification of common tools and stimulate maximum re-use of components coming from other funded projects e.g., interoperable identity and credential management tools, common packaging solutions, tools for decentralised social media.
Applicants should seek active collaboration with other initiatives addressing internet commons of relevance to 3Cs at national, European levels and beyond Europe including with European technology industries.
Applicants should demonstrate their experience and understanding of Open-Source communities and their expertise covering the full Open-Source life cycle through proven track record including years of experience and indication of volume of Open-Source projects supported.
The Commission considers that proposals in this topic with an overall duration of typically 36 months would allow these outcomes to be addressed appropriately. Nonetheless, this does not preclude submission and selection of proposals requesting other durations. 
In this topic the integration of the gender dimension (sex and gender analysis) in research and innovation content is not a mandatory requirement.
Financial support to third parties 
Third parties will be funded through projects typically in the EUR 50 000 to 150 000 range per project, with indicative duration of 9 to 12 months. The consortium should provide the programme logic for the third-party projects, managing the projects lifecycle, and provide the necessary technical and non-technical support: these tasks cannot be implemented using the budget earmarked for the financial support to third parties.
**conditions:** General conditions
1. Admissibility Conditions: Proposal page limit and layout
are described in Annex A and Annex E of the Horizon Europe Work Programme General Annexes.
Proposal page limits and layout: described in Part B of the Application Form available in the Submission System.

2. Eligible Countries
are described in Annex B of the Work Programme General Annexes.
A number of non-EU/non-Associated Countries that are not automatically eligible for funding have made specific provisions for making funding available for their participants in Horizon Europe projects. See the information in the Horizon Europe Programme Guide.

3. Other Eligible Conditions
Subject to restrictions for the protection of European communication networks.

Described in Annex B of the Work Programme General Annexes.

4. Financial and operational capacity and exclusion
are described in Annex C of the Work Programme General Annexes.

5a. Evaluation and award: Award criteria, scoring and thresholds
are described in Annex D of the Work Programme General Annexes.

5b. Evaluation and award: Submission and evaluation processes
are described in Annex F of the Work Programme General Annexes and the Online Manual.

5c. Evaluation and award: Indicative timeline for evaluation and grant agreement
is described in Annex F of the Work Programme General Annexes.

6. Legal and financial set-up of the grants
Beneficiaries may provide financial support to third parties. The support to third parties can only be provided in the form of grants. The maximum amount to be granted to each third party is EUR 400 000 to allow 1/ cases where a given legal entity may receive several grants (e.g. from different calls) 2/ reaching the maturity level for third party’s project to ensure sustainability with multiple awards.
To support and mobilise internet innovators, a maximum of 70% of the total requested EU contribution could be allocated to financial support to third parties, selected through open calls.

Described in Annex G of the Work Programme General Annexes.

Specific conditions
 are described in the specific topic of the Work Programme.

Application and evaluation forms and model grant agreement (MGA):
 Application form templates — the application form specific to this call is available in the Submission System
Standard application form (HE RIA, IA)
Evaluation form templates — will be used with the necessary adaptations 
Standard evaluation form (HE RIA, IA) 

Guidance
HE Programme Guide 
Model Grant Agreements (MGA)
HE MGA 

Call-specific instructions 
Information on financial support to third parties (HE) 

Additional documents:
 HE Main Work Programme 2025 – 1. General Introduction
HE Main Work Programme 2025 – 7. Digital, Industry and Space
HE Main Work Programme 2025 – 14. General Annexes

HE Programme Guide
HE Framework Programme 2021/695
HE Specific Programme Decision 2021/764 
EU Financial Regulation 2024/2509
Rules for Legal Entity Validation, LEAR Appointment and Financial Capacity Assessment 
EU Grants AGA — Annotated Model Grant Agreement 
Funding & Tenders Portal Online Manual 
Funding & Tenders Portal Terms and Conditions 
Funding & Tenders Portal Privacy Statement
**action type:** HORIZON  Research and Innovation Actions
**budget:** 
  **budget Years Columns:** 
    - 2025
  **budget Topic Action Map:** 
    **110947:** 
      -         **action:** HORIZON-CL4-2025-03-DIGITAL-EMERGING-02 - HORIZON-RIA HORIZON  Research and Innovation Actions
        **budget Year Map:** 
          **2025:** 10000000
        **deadline Dates:** 
          - 2025-10-02
        **deadline Model:** single-stage
        **expected Grants:** 2
        **max Contribution:** 5000000
        **min Contribution:** 5000000
        **planned Opening Date:** 2025-06-10
    **110948:** 
      -         **action:** HORIZON-CL4-2025-03-HUMAN-14 - HORIZON-RIA HORIZON  Research and Innovation Actions
        **budget Year Map:** 
          **2025:** 43000000
        **deadline Dates:** 
          - 2025-10-02
        **deadline Model:** single-stage
        **expected Grants:** 7
        **max Contribution:** 6000000
        **min Contribution:** 5000000
        **planned Opening Date:** 2025-06-10
    **110949:** 
      -         **action:** HORIZON-CL4-2025-03-HUMAN-16 - HORIZON-RIA HORIZON  Research and Innovation Actions
        **budget Year Map:** 
          **2025:** 14500000
        **deadline Dates:** 
          - 2025-10-02
        **deadline Model:** single-stage
        **expected Grants:** 9
        **max Contribution:** 3000000
        **min Contribution:** 1000000
        **planned Opening Date:** 2025-06-10
    **110950:** 
      -         **action:** HORIZON-CL4-2025-03-DATA-09 - HORIZON-CSA HORIZON Coordination and Support Actions
        **budget Year Map:** 
          **2025:** 2500000
        **deadline Dates:** 
          - 2025-10-02
        **deadline Model:** single-stage
        **expected Grants:** 1
        **max Contribution:** 2500000
        **min Contribution:** 1800000
        **planned Opening Date:** 2025-06-10
    **110951:** 
      -         **action:** HORIZON-CL4-2025-03-DIGITAL-EMERGING-03 - HORIZON-RIA HORIZON  Research and Innovation Actions
        **budget Year Map:** 
          **2025:** 8000000
        **deadline Dates:** 
          - 2025-10-02
        **deadline Model:** single-stage
        **expected Grants:** 3
        **max Contribution:** 2700000
        **min Contribution:** 2500000
        **planned Opening Date:** 2025-06-10
    **110952:** 
      -         **action:** HORIZON-CL4-2025-03-MATERIALS-47 - HORIZON-RIA HORIZON  Research and Innovation Actions
        **budget Year Map:** 
          **2025:** 15000000
        **deadline Dates:** 
          - 2025-10-02
        **deadline Model:** single-stage
        **expected Grants:** 3
        **max Contribution:** 5000000
        **min Contribution:** 5000000
        **planned Opening Date:** 2025-06-10
    **110953:** 
      -         **action:** HORIZON-CL4-2025-03-DIGITAL-EMERGING-01 - HORIZON-CSA HORIZON Coordination and Support Actions
        **budget Year Map:** 
          **2025:** 4500000
        **deadline Dates:** 
          - 2025-10-02
        **deadline Model:** single-stage
        **expected Grants:** 1
        **max Contribution:** 4500000
        **min Contribution:** 4500000
        **planned Opening Date:** 2025-06-10
    **110954:** 
      -         **action:** HORIZON-CL4-2025-03-DIGITAL-EMERGING-07 - HORIZON-RIA HORIZON  Research and Innovation Actions
        **budget Year Map:** 
          **2025:** 85000000
        **deadline Dates:** 
          - 2025-10-02
        **deadline Model:** single-stage
        **expected Grants:** 2
        **max Contribution:** 45000000
        **min Contribution:** 40000000
        **planned Opening Date:** 2025-06-10
    **110955:** 
      -         **action:** HORIZON-CL4-2025-03-DATA-08 - HORIZON-RIA HORIZON  Research and Innovation Actions
        **budget Year Map:** 
          **2025:** 75000000
        **deadline Dates:** 
          - 2025-10-02
        **deadline Model:** single-stage
        **expected Grants:** 1
        **max Contribution:** 75000000
        **min Contribution:** 75000000
        **planned Opening Date:** 2025-06-10
    **110956:** 
      -         **action:** HORIZON-CL4-2025-03-HUMAN-19 - HORIZON-CSA HORIZON Coordination and Support Actions
        **budget Year Map:** 
          **2025:** 3000000
        **deadline Dates:** 
          - 2025-10-02
        **deadline Model:** single-stage
        **expected Grants:** 1
        **max Contribution:** 3000000
        **min Contribution:** 3000000
        **planned Opening Date:** 2025-06-10
    **110957:** 
      -         **action:** HORIZON-CL4-2025-03-DIGITAL-EMERGING-08 - HORIZON-CSA HORIZON Coordination and Support Actions
        **budget Year Map:** 
          **2025:** 1000000
        **deadline Dates:** 
          - 2025-10-02
        **deadline Model:** single-stage
        **expected Grants:** 1
        **max Contribution:** 1000000
        **min Contribution:** 1000000
        **planned Opening Date:** 2025-06-10
    **110958:** 
      -         **action:** HORIZON-CL4-2025-03-DATA-12 - HORIZON-CSA HORIZON Coordination and Support Actions
        **budget Year Map:** 
          **2025:** 2100000
        **deadline Dates:** 
          - 2025-10-02
        **deadline Model:** single-stage
        **expected Grants:** 1
        **max Contribution:** 2100000
        **min Contribution:** 1900000
        **planned Opening Date:** 2025-06-10
    **110959:** 
      -         **action:** HORIZON-CL4-2025-03-DATA-13 - HORIZON-IA HORIZON Innovation Actions
        **budget Year Map:** 
          **2025:** 45000000
        **deadline Dates:** 
          - 2025-10-02
        **deadline Model:** single-stage
        **expected Grants:** 6
        **max Contribution:** 9000000
        **min Contribution:** 7000000
        **planned Opening Date:** 2025-06-10
    **110960:** 
      -         **action:** HORIZON-CL4-2025-03-HUMAN-18 - HORIZON-CSA HORIZON Coordination and Support Actions
        **budget Year Map:** 
          **2025:** 3000000
        **deadline Dates:** 
          - 2025-10-02
        **deadline Model:** single-stage
        **expected Grants:** 1
        **max Contribution:** 3000000
        **min Contribution:** 3000000
        **planned Opening Date:** 2025-06-10
    **110961:** 
      -         **action:** HORIZON-CL4-2025-03-HUMAN-15 - HORIZON-IA HORIZON Innovation Actions
        **budget Year Map:** 
          **2025:** 20000000
        **deadline Dates:** 
          - 2025-10-02
        **deadline Model:** single-stage
        **expected Grants:** 5
        **max Contribution:** 5000000
        **min Contribution:** 4000000
        **planned Opening Date:** 2025-06-10
    **110962:** 
      -         **action:** HORIZON-CL4-2025-03-DATA-10 - HORIZON-CSA HORIZON Coordination and Support Actions
        **budget Year Map:** 
          **2025:** 2500000
        **deadline Dates:** 
          - 2025-10-02
        **deadline Model:** single-stage
        **expected Grants:** 1
        **max Contribution:** 2500000
        **min Contribution:** 1800000
        **planned Opening Date:** 2025-06-10
    **110963:** 
      -         **action:** HORIZON-CL4-2025-03-DIGITAL-EMERGING-04 - HORIZON-CSA HORIZON Coordination and Support Actions
        **budget Year Map:** 
          **2025:** 2500000
        **deadline Dates:** 
          - 2025-10-02
        **deadline Model:** single-stage
        **expected Grants:** 1
        **max Contribution:** 2500000
        **min Contribution:** 2500000
        **planned Opening Date:** 2025-06-10
    **110964:** 
      -         **action:** HORIZON-CL4-2025-03-DIGITAL-EMERGING-09 - HORIZON-RIA HORIZON  Research and Innovation Actions
        **budget Year Map:** 
          **2025:** 45000000
        **deadline Dates:** 
          - 2025-10-02
        **deadline Model:** single-stage
        **expected Grants:** 3
        **max Contribution:** 15000000
        **min Contribution:** 15000000
        **planned Opening Date:** 2025-06-10
    **110965:** 
      -         **action:** HORIZON-CL4-2025-03-DATA-11 - HORIZON-RIA HORIZON  Research and Innovation Actions
        **budget Year Map:** 
          **2025:** 10000000
        **deadline Dates:** 
          - 2025-10-02
        **deadline Model:** single-stage
        **expected Grants:** 1
        **max Contribution:** 10000000
        **min Contribution:** 10000000
        **planned Opening Date:** 2025-06-10
    **110966:** 
      -         **action:** HORIZON-CL4-2025-03-MATERIALS-46 - HORIZON-RIA HORIZON  Research and Innovation Actions
        **budget Year Map:** 
          **2025:** 10000000
        **deadline Dates:** 
          - 2025-10-02
        **deadline Model:** single-stage
        **expected Grants:** 2
        **max Contribution:** 5000000
        **min Contribution:** 5000000
        **planned Opening Date:** 2025-06-10
    **110967:** 
      -         **action:** HORIZON-CL4-2025-03-HUMAN-17 - HORIZON-CSA HORIZON Coordination and Support Actions
        **budget Year Map:** 
          **2025:** 2500000
        **deadline Dates:** 
          - 2025-10-02
        **deadline Model:** single-stage
        **expected Grants:** 1
        **max Contribution:** 2500000
        **min Contribution:** 2500000
        **planned Opening Date:** 2025-06-10
**keywords:** HORIZON-CL4-2025-03-DATA-11, HORIZON-CL4-2025-03, Communication engineering and systems telecommunications, Internet architectures, Open Source Software, Open hardware, Software engineering, operating systems, computer languages
**last synced at:** 2026-11-09T17:23:17.403+00:00

## Review record

No independent verification record is available.

## Source metadata