European Commission announces Once-Only Technical System as an open-source software
18 January 2026 | 3 minutes read
On 14 January 2025, the European Commission has announced the gradual release of its Once-Only Technical System(opens in a new tab) (OOTS) as open-source software, now available under the European Union Public Licence (EUPL) at code.europa.eu. This release includes the OOTS Common Services(opens in a new tab) and the EMREX Bridge(opens in a new tab) components, marking significant progress in the Commission’s commitment to transparency and interoperability.
This Commission's open-source initiative aligns with its Open Source Software Strategy (2020) (opens in a new tab) and Software Reuse Decision (2021)(opens in a new tab), promoting public access and reuse of software developed by the Commission. The EUPL licence ensures comprehensive distribution while maintaining openness and legal compliance within EU regulations. As a copyleft licence, EUPL retains derivative works' openness and compatibility with other licences such as GPL and LGPL.
The release process will be incremental, with distinct repositories created to clearly separate publications from core technical components. Main repositories include:
This initiative empowers users to leverage the four freedoms of open-source software: use, copy, modify, and distribute. The Commission hopes this step will foster collaboration, enhance the adoption of interoperable digital solutions, and drive innovation across Europe’s digital landscape.
The Once-Only Technical System is a digital framework that ensures that citizens and businesses provide information to public authorities only once, with subsequent sharing among authorities minimising administrative burdens by simplifying cross-border administrative procedures. By making cross-border administrative procedures simple, digital, and seamless, the EU can dramatically lower associated costs, enabling businesses to scale faster across borders, accelerating innovation, and allowing citizens to work and move freely within the Single Market.