Author: Italo Vignoli

When we create or share a document – whether a simple text, complex spreadsheet or professional presentation – we make a choice that goes far beyond the file extension. This is because the format gives us, or takes away, control over the content.

This post compares the Open Document Format (ODF) with proprietary formats such as DOCX, XLSX and PPTX. The comparison is not just about compatibility, but also about freedom, security, costs, transparency, and our long-term digital future.

We have already discussed ODF, and we will continue to do so until its 10th anniversary as an ISO/IEC standard in May 2026, because it is the only open standard available to users. We hope that an increasing number of users will understand how important it is for them to use it to have complete and lasting control over the content they have created, i.e. for their digital freedom, rather than for those of us who support it.
ODF is the native format of LibreOffice and other programmes that use the LibreOffice Technology platform. These programmes offer the same functionality, flexibility, security, robustness and interoperability as applications that promote proprietary formats, but without the lock-in strategy.

Incidentally, even so-called open-source applications (read their AGPL licence to understand why we say “so-called”) handle documents in ODF format, yet continue to promote their own formats, preventing users from having full control over their content – because this would jeopardise their business strategy.

So, what are proprietary formats?

They are developed and controlled by a single company and are typically only fully supported within that company’s ecosystem. Common examples include .docx, .xlsx and .pptx (Microsoft), as well as .pages, .numbers and .key (Apple) and .gdoc, .gsheet and .gslides (Google). While the specifications for these formats may be public, this does not mean they are completely open, as support is always limited by what the provider allows or documents, and is dictated by their commercial strategies.

Comparison between ODF and proprietary formats

1. Control and vendor lock-in

ODF

• Completely open and standardised
• Anyone can implement or use it without legal restrictions
• The user, not the software provider, controls the documents

Proprietary formats

• Designed and controlled by a single provider
• File characteristics and behaviour may change without notice
• Users are often forced to update their software in order to access their documents

Example: If Microsoft changes how DOCX handles embedded fonts or custom styles, users of older versions of Microsoft software or compatible applications may have difficulty viewing or reading files.

2. Interoperability and compatibility

ODF

• Designed with interoperability in mind
• Promotes consistency in formatting and behaviour across different platforms and software
• Facilitates the development of a multi-vendor ecosystem

Proprietary formats

• Optimised for performance within the vendor’s software
• Third-party implementations often encounter compatibility issues
• File rendering may vary depending on the platform, particularly for advanced formatting

Example: A spreadsheet with complex macros in .xlsx format that works correctly with Excel may not work, or may lose functionality, when used with LibreOffice Calc or Google Sheets.

3. Transparency and trust

ODF

• The format is documented, and matches the documentation
• Data storage is also documented, and users control their files’ location
• There are no secrets or hidden metadata, and the XML file is user readable

Proprietary formats

• They may contain undocumented metadata or behaviour, and the XML file is not user readable
• The complex and opaque structure of the files can create security issues, and files’ location is not controlled by the user
• It is not always clear what information is embedded (e.g. edit history and comments)

Example: a DOCX file may contain residual metadata, such as the names of authors, the date and time of changes, and comments, even after they have been removed.

4. Digital preservation and long-term access

ODF

• Designed for compatibility, interoperability, and long-term archiving
• Recommended by governments (UK, Taiwan, the Netherlands and France) and supranational organisations (EU, NATO)
• Open and future-proof, with regular updates from a known Technical Committee overseen by OASIS

Proprietary formats

• Risk of format obsolescence (remember .doc, .wps and .wpd?)
• Require specific software versions to access older files

Example: a government archive using ODF can be confident that it will still be able to access documents in 20 years’ time, while this is not guaranteed by proprietary formats, which are closely linked to the lifecycles of corporate products.

5. Public sector and legal obligations

Governments and institutions around the world should switch to open standards to ensure data sovereignty and reduce dependence on specific suppliers.

• The UK, Germany, the Netherlands and Taiwan have all launched initiatives to promote ODF
• The European Union’s open-source strategy recommends using ODF in all public administrations
• Italy’s Digital Administration Code supports open formats for public documents to ensure long-term accessibility

Why? Because public data should be open and accessible, not locked behind corporate paywalls or licence terms.

6. Costs and licences

ODF

• Free to use and implement
• No licence fees, subscription costs or vendor lock-in

Proprietary formats

• Almost always tied to paid software (e.g. Microsoft 365)
• In some cases, access requires a cloud account and/or an active subscription
• There are often restrictions on redistribution and format conversion

Example: If a school switches from Microsoft Office to LibreOffice and adopts the OpenDocument Format (ODF), it can save thousands of euros in licence costs without sacrificing functionality for students.

7. Innovation and community support

ODF

• Developed transparently by a global community
• Supported by several applications, both open source and proprietary
• Open to improvements by anyone, under the Technical Committee overview

Proprietary formats

• Innovation is centralised and constrained by the company roadmap, and development is closed and not transparent
• Feature priorities are determined by revenue, and not by user needs

Example: Users can propose new features for ODF, contribute code, and fund development, all without having to wait for the company’s priorities to align with their own.

Conclusion: Why ODF matters

The choice of ODF is not linked to ideology or politics. It is a choice that offers users significant practical benefits: complete control over their data; independence from a single company’s tools, strategies and business model; the ability to access and share documents more reliably on any hardware platform or operating system; and support for an ecosystem where open standards drive progress rather than profit margins. ODF stands for transparency, freedom, and openness to the future. Try it, it’s easy and doesn’t cost anything. Download LibreOffice and you’re done.

Consider the history of control over user files, whether for organisations or individuals

Think about all the documents you have created in your lifetime: School assignments. Work presentations and reports. Household budgets. Letters. Perhaps even a personal diary or your CV.

Now imagine this: a few years go by, and when you try to open one of those files, it doesn’t work. The software has disappeared. Or it has been updated and no longer supports that format. Or you have to pay to unlock it.

It’s not just frustrating. It’s a real problem. That’s why the Open Document Format (ODF) was created: it’s a file format that allows computers to save documents such as letters, spreadsheets and presentations. You can recognise these files by their extensions: .odt for text files, .ods for spreadsheets and .odp for presentations.

What makes ODF special is that it is an open, transparent format that doesn’t hide anything from users. This means that anyone can use it freely; no company owns or controls it; and it is designed to work with different software, even years later. In short, it gives you control over your documents.

Let’s look at some everyday situations in which ODF can be useful:

Long-term access: you write your memoirs or your family history. Ten years later, you want to read or share them. With ODF, you don’t have to worry about the software becoming unavailable or obsolete.

Barrier-free education: A teacher asks students to submit their assignments digitally. With ODF, there is no need to purchase expensive software, as you can use a free tool such as LibreOffice instead.

Job search and consulting: create your CV in an open format so that anyone, regardless of their operating system (Windows, macOS or Linux) or application, can open it without encountering any formatting errors. You don’t even have to buy the software.

Sharing files with other users: you can send a document to a colleague or family member and they can open it without any problems, regardless of the programme they use. This is the advantage of a format that does not “belong” to a single company.

Public services: official documents in an open format can be accessed by everyone forever without them having to purchase or update software.

Unfortunately, most people forego all this because they use formats such as .docx (Word) or .xlsx (Excel). These are proprietary formats exclusively owned by Microsoft and can change at any time depending on their business strategies. Microsoft may require a subscription fee for a specific version, as older files may not be compatible with newer ones.

Proprietary formats can also cause problems when documents are opened with a different version of the same application, as the text and images may move and the document may look different. Sometimes, files do not open because the format is not recognised. This is not only annoying, but also risky if the file is important.

This is known as ‘lock-in’, a strategy that prevents users from choosing the software they prefer because migrating to a different format could result in the loss of all their content.

ODF, on the other hand, means freedom of choice, no restrictions, reduced costs, privacy, openness to the future and trust in technology. You don’t need to be a technology expert to use it; you just need to understand why it was created and why it has continued to grow for 20 years. Using ODF is like saving your documents in your own safe: it won’t suddenly disappear or require you to pay a monthly fee.

ODF also means security and transparency. ODF files are ZIP containers that use simple XML syntax, which any user can understand. This makes security checks much easier, allowing for automation and integration with companies’ CMS/ERP systems.

The digital agenda has always emphasised open standards, interoperability, and data portability. ODF fits perfectly into this landscape, not only replacing .docx or .xlsx, but also rejecting software that treats user data as a product.

ODF gives users full control over their documents. This is not just a technical detail; it ensures that documents belong to their creators, not the software used to process them. ODF enables us to assert ownership of our documents.

An introduction to the Open Document Format

The documents we create today, whether reports, spreadsheets or presentations, are essential for communicating, sharing and storing knowledge. However, the format in which these documents are saved often goes unnoticed. This is where the Open Document Format (ODF) comes in. ODF is a technical standard and a tool that ensures documents remain accessible, editable and usable over time without being tied to a specific vendor or product.

Approved by OASIS as an open standard document format in May 2005 and by ISO/IEC in May 2006, ODF has been around for over 20 years. Despite 20 years having passed, most productivity software users are not familiar with the format and therefore do not use it, as it is not as widespread as its proprietary counterpart, Microsoft OOXML.

This means that a huge number of documents — equivalent to over 100 zettabytes of data in 2025 — are subject to the commercial strategies of a company and completely beyond the control of their authors. These authors may suddenly find themselves unable to manage their own content unless they use specific software.

This also means that the enormous wealth of information contained in these documents does not contribute to the growth of collective intelligence because they are limited in terms of interoperability due to being tied to a single, specific, proprietary software.

Furthermore, Microsoft’s touted backward compatibility feature prevents true innovation in document formats because the presence of proprietary elements from old binary formats, which are not included in the ODF standard, forces documents to remain with technologies that have long been obsolete and incompatible with future developments.

What is ODF?

ODF is an open standard for saving and exchanging office documents. It includes text files (.odt), spreadsheets (.ods), presentations (.odp), and other types of documents, such as drawings (.odg). Developed by OASIS, an organisation that promotes structured information standards, it was approved by ISO/IEC as the international standard ISO/IEC 26300 in 2006.

Put simply, ODF is a universal language for documents, ensuring they can be read and written by any compatible software without locking users into a single ecosystem.

To understand the importance of ODF, it is helpful to know how proprietary formats work. When a document is saved in a Microsoft format, such as .docx, or an Apple format, such as .pages, it is often designed to work best with that company’s software only. Over time, this can cause problems such as limited compatibility, vendor lock-in, and the risk of obsolescence if the proprietary format is abandoned or changed significantly, as older documents may become unreadable.

ODF avoids these problems. It is completely open and free, meaning that anyone can implement it in their software, and users can switch between tools without losing access to their files.

ODF is not limited to text documents, but includes a wide range of office document types, including .odt (OpenDocument Text) for text documents such as reports, letters and books; .ods (OpenDocument Spreadsheet) for data analysis, tables and financial models; .odp (OpenDocument Presentation) for presentations with visual content; .odg (OpenDocument Graphics) for diagrams and vector graphics, as well as documents containing text and images; and .odf (OpenFormula) for formulas used in ODS spreadsheets.

Each of these document types is structured in such a way as to allow maximum compatibility while maintaining formatting and advanced software features.

How does ODF compare with Microsoft document formats?

Feature	ODF	Microsoft (docx. xlsx, pptx)
Open Standard	Yes	No
Long Term Archiving	Solid Support	Risk of Format Changes Risk of Online Dependency
Offline Support	Fully Supported	Supported
Editable without Vendor Software	Yes	Limited

Common misconceptions about ODF

It is not as feature-rich as .docx or .xlsx

False. ODF supports complex formatting, styles, images, tables, charts, macros and more. Its feature set is robust and evolving thanks to contributions from a global community of developers and users.

No one uses ODF

This is also false. In fact, millions of users worldwide use ODF-compatible software every day. LibreOffice alone has tens of millions of active users worldwide.

It doesn’t work with my existing documents

ODF-compatible software, such as LibreOffice, can open, edit and export many formats, including .docx and .xlsx. Switching to ODF is easy and you won’t lose access to your existing files.

The future of ODF

The growing importance of digital documents in every sector, including education, public administration and business, is bound to impact the adoption of the ODF format because users cannot continue to use a format that disadvantages them in every way. Furthermore, the number of countries adopting policies based on open standards and demanding transparency and control over their data is growing all the time, and this can only lead to increased adoption of ODF in the long term.

Documents should belong to their authors, not to a software vendor through the file format used. In the case of a country, documents should belong to its citizens. ODF is the only effective way to regain control and ensure that data remains open, accessible and future-proof. ODF embodies the principles of digital freedom, collaboration, and user empowerment.

Whether you are an individual seeking control over your digital life, a teacher aiming to share knowledge using open tools to ensure its long-term availability to the community, a public official seeking long-term transparency, or a politician representing citizens’ interests, ODF is the smart, sustainable choice.

DISCLAIMER: Artificial Intelligence has helped in putting together background data in a matter of seconds, thus dramatically reducing the time needed to draft the article. I have over 4GB of background documents on my online storage, and although I have read most of them, it is impossible for my humble brain to retain all information. Here, Artificial Intelligence helps a lot, especially a 70 years old guy.

On May 1st, 2005, the Open Document Format (ODF) become an OASIS standard. One year after, it became an ISO/IEC standard. After two decades, it is the only true open standard for document formats available on the market, and the only one protecting users from proprietary lock in and ensuring a full control over contents. The presentation provides an overview over ODF features and explains why ODF should be used versus Microsoft OOXML (DOCX, XLSX and PPTX).

PeerTube: https://peertube.opencloud.lu/w/2b9JeZw1M884V5BK21RioW

YouTube: https://youtu.be/Z-Xo9v9-1YU (please note that once you leave this blog to access the video, a different set of privacy rules will apply)

Open Document Format (ODF) has been designed as a document standard for the next 20-50 years, to liberate users from the lock-in strategy built into yesterday’s and today’s proprietary formats and foster interoperability. On the contrary, OOXML – approved by ISO/IEC in 2008 in a version never implemented by MS Office – has been designed as a document pseudo-standard format to propagate yesterday’s document issues and lock-in strategy for the next 20-50 years, to the detriment of users and interoperability.

The philosophy behind the ODF standard document format was to design a mechanism in a vendor neutral manner from the ground up, using existing standards wherever possible. Although this means that software vendors had to tweak their individual packages more than if they continued down their original routes, the benefits for interoperability were important enough to justify this objective. The OOXML pseudo-standard document format was designed by Microsoft for Microsoft products, and to interoperate with the Microsoft environment. Little thought appears to have been exercised for interoperability with non-Microsoft environments, or compliance with established vendor-neutral standards.