Open Document Standards: The Core of Digital Sovereignty in European Office Suites

The Context of Euro-Office

Euro-Office is a new European productivity project spearheaded by Nextcloud and IONOS. It is a fork of ONLYOFFICE, a self-hosted, web-based office suite designed for organizations and governments seeking collaborative document editing on their own infrastructure. A central goal is to move away from office software with ties to Russia, addressing concerns over digital sovereignty. However, the question remains: does switching vendors alone guarantee true independence?

Origins and Goals

Announced in early 2025, Euro-Office aims to provide a fully European-controlled alternative for public sector and enterprise document collaboration. Its FAQ emphasizes "great MS compatibility," hinting at a focus on Microsoft Office formats. Yet the project’s GitHub repository lists support for ODF (Open Document Format) alongside DOCX, PPTX, and XLSX. This has sparked debate about which format will be the native default for documents created and shared among European bodies.

The Document Foundation's Concerns

The Document Foundation (TDF), the nonprofit behind LibreOffice, has publicly questioned Euro-Office’s commitment to digital sovereignty. In an open letter to European citizens at the end of March, TDF argued that true sovereignty is not achieved by simply switching office software vendors. Real independence requires:

• Open document formats that are not controlled by any single entity
• Open fonts to avoid licensing dependencies
• Continuity of expertise so that users are not locked into new proprietary systems

TDF specifically asked Euro-Office what document format would be its native default, noting that the project’s launch press release mentioned ODF only as a supported format, not as the primary standard. As of now, Euro-Office has not replied.

Why Document Format Matters

Supporting a format and making it the native default are two different things. A suite that defaults to OOXML (the format used by Microsoft Office) remains structurally dependent on decisions made by Microsoft, regardless of where it is hosted. OOXML is an ISO standard, but it is designed and controlled entirely by Microsoft. In contrast, ODF (Open Document Format) is developed openly through a community-driven process, with no single company holding the reins.

ODF vs OOXML: The Key Differences

ODF, also an ISO standard, is the format championed by TDF. It is inherently interoperable and free from vendor lock-in. Euro-Office’s FAQ frames its offering around "great MS compatibility," which suggests that OOXML may be the default or heavily promoted format. This would undermine the goal of breaking dependency on American-controlled technology. Germany, for instance, has already mandated ODF by law, setting a precedent for other European nations.

Implications for European Institutions

The distinction between supporting a format and defaulting to it is critical for any European institution that genuinely wants to escape the Office ecosystem. Merely moving servers from Redmond to a European data center does not achieve sovereignty if the document format remains closed and proprietary. TDF’s question is now public, and it is not going away. If Euro-Office continues to remain silent, it risks losing credibility as a sovereign solution.

The Path Forward

Euro-Office’s choice of native document format will signal its true intentions. An explicit commitment to ODF as the default format for all new documents would align with the project’s stated sovereignty goals. The Document Foundation has invited Euro-Office to clarify its position, and the European open-source community watches closely. Until then, the question lingers: is Euro-Office a step toward digital independence, or just a different kind of lock-in?