Office Open XML

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Office Open XML
File extension : .docx, .xlsx, .pptx
MIME type : application / vnd.openxmlformats-officedocument.wordprocessingml.document, application / vnd.openxmlformats-officedocument.spreadsheetml.sheet, application / vnd.openxmlformats-officedocument.presentationml.presentation
Developed by: Microsoft ,
Ecma International
Type: Office applications
Extended by: ZIP , XML , DOC , XLS , PPT
Standard (s) : ECMA-376 ,

ISO / IEC 29500-1: 2008 , ISO / IEC 29500-2: 2008 , ISO / IEC 29500-3: 2008 , ISO / IEC 29500-4: 2008

Website : The Microsoft Office Open XML Format

Office Open XML , also known as OOXML or Microsoft Open XML (MOX) (ECMA-376 Office Open XML File Formats or ISO / IEC 29500 Information technology - Office Open XML formats ), describes file formats developed by Microsoft for saving office documents on XML -Basis, which should enable data or file exchange between different office application packages.

A total of three different versions of OOXML were specified and standardized, which are not compatible with each other: Version "ECMA-376" and "ISO / IEC 29500: 2008" (in two versions, "Transitional" and "Strict").

The first format specification was submitted to Ecma International by Microsoft for standardization. This took place on December 7, 2006 as the Ecma standard ECMA-376 . It was first published as the ISO / IEC 29500 standard on November 19, 2008 in a modified version.

Before that, however, the XML-based, but manufacturer-independent and open-source specification OpenDocument was already adopted as the standard for the interoperability of office documents and applications by ISO and IEC , and published in 2006 as the international standard ISO / IEC 26300. In contrast to the Microsoft Open XML standard, the O ASIS OpenDocument standard, according to Microsoft, did not focus on the requirements, boundary conditions and experiences of Microsoft customers. MOX / OOXML should be tailored more precisely to the “special” working methods of Microsoft Office applications.


Due to the widespread use of Microsoft Office , the associated binary and proprietary file formats of Microsoft Word , Microsoft Excel and Microsoft PowerPoint had established themselves as a de facto standard for document exchange in many areas .

The structure of these Office formats was not openly documented, but had to be licensed from Microsoft. Since the costs and, above all, the license conditions are not acceptable for all providers, some competitors (especially open source projects) were forced to find out the structure of the file formats through reverse engineering . Due to the problems inherent in reverse engineering and the fact that the file formats are closely linked to the inner workings of Microsoft Office applications, incorrect generation and display of file contents could result from appropriately developed competing applications. Microsoft has now published the format specification.

In order to simplify the automated creation and processing of Microsoft Office spreadsheet documents, an XML -based file format ( XML Spreadsheet ) was introduced with Microsoft Excel 2002 , which, however, can only save part of the Excel functionality.

With Microsoft Office 2003, XML support was expanded and new XML-based file formats were introduced, particularly in Microsoft Word.

For Microsoft Office 2007, the XML-based file formats have been revised and made the new standard file format. This file format forms the basis of Office Open XML .

The standard for file formats of office documents ISO / IEC 26300 ( OpenDocument 1.0, ODF for short) , which was also based on XML and was internationally standardized in 2006 , was originally developed by Sun Microsystems and is still maintained and further developed by the manufacturer-independent organization OASIS , is now directly supported by Microsoft in all Office applications, but has been rejected as the original standard file format for Microsoft Office. Among other things, because it is supposedly still too much based on the file format - and thus the working method and range of functions - of and is not suitable for displaying all existing Microsoft Office documents.

Proponents of ODF counter this, however, by saying that ODF can of course directly map all incompatible properties of Microsoft Office documents through proprietary extensions.


For some time, it has been  demanded - above all by governments (e.g. the US state of Massachusetts ) or the EU - that in the future only openly documented, manufacturer-independent, standardized file formats should be used in order to avoid lock-in effects and to ensure interoperability and ensure long-term access to file contents. Because of these demands, Microsoft presented the Microsoft Office 2007 file format to Ecma International for standardization. The standardization takes place there as part of the Technical Committee 45 (TC45).

The standardization process are Apple , Barclays Capital, BP , The British Library , Essilor , Intel , the The United States Library of Congress , Microsoft , NextPage , Novell , Statoil ASA and Toshiba participated.

Office Open XML was approved as Ecma Standard 376 by the Ecma International General Meeting on December 7, 2006.

In December 2006, Office Open XML was submitted to ISO as ISO / IEC CD 29500 for standardization using the JTC 1 Fast Track Process. In a vote in September 2007, it was unable to achieve the approval required to be accepted as an ISO standard.

After a meeting scheduled in February 2008 - at which the numerous comments that were submitted when voting in September 2007 - the voting ISO members had the opportunity to change their originally cast vote until the end of March 2008. In the course of the national votes, irregularities were repeatedly reported. The FFII accused Microsoft of filling up the standardization bodies of various countries with straw men . In Norway, the national standardization body is said to have ignored a clear rejection of 21 no and 2 yes votes by its members.

In an open letter , ISO / IEC-SC-34 members disapproved of the personal attacks made against them during the standardization process.

As the ISO announced on April 2, 2008, the draft standard received the necessary majority of votes and was initially accepted as the ISO draft ISO / IEC DIS 29500. However, the national standardization organizations of South Africa (SABS), Brazil (ABNT), India and Venezuela have objected to the publication of ISO / IEC 29500 as a standard within the allotted time. A decision by the responsible bodies on the objections was announced for the end of June 2008; until then, standardization and publication were suspended. On August 15, 2008, the ISO announced that the objections of the national standardization organizations had been rejected and the standard was now released for publication. A complete implementation of the standard does not yet exist, and Microsoft Office 2007 does not meet all requirements either. It was published as the ISO / IEC 29500 standard on November 19, 2008 in four parts: There is now a new edition with publication in September 2012.

  • ISO / IEC 29500-1 - Office Open XML File Formats - Part 1: Fundamentals and Markup Language Reference
  • ISO / IEC 29500-2 - Office Open XML File Formats - Part 2: Open Packaging Conventions
  • ISO / IEC 29500-3 - Office Open XML File Formats - Part 3: Markup Compatibility and Extensibility
  • ISO / IEC 29500-4 - Office Open XML File Formats - Part 4: Transitional Migration Features

The four documents can be downloaded free of charge from ISO as publicly available standards .


Like all Ecma International standards, Office Open XML is freely available and can be copied.

In a covenant not to sue , Microsoft has declared that it irrevocably waives any enforcement of all patents required for a compliant implementation of the Office 2003 XML Reference Schemas specification in relation to program parts that implement this specification. The law firm Baker & McKenzie checked the content and validity of this covenant on behalf of Microsoft, among other things , and determined in a study that no license is required to use Office Open XML.

In addition, Microsoft has included the Office 2003 XML Reference Scheme and the Office Open XML 1.0 ECMA 376 specification in the Microsoft Open Specification Promise (OSP). In the OSP, Microsoft promises to forego the enforcement of patents against program parts that implement the specified specifications. However, the OSP only refers to the versions of the respective specifications explicitly listed by Microsoft. In addition, this does not apply to any patent claims by third parties.

According to the Software Freedom Law Center , the promise would only extend to new versions if Microsoft participates in standardization activities. Ending standardization activities on the part of Microsoft would make the promise void.


Office Open XML consists of a specification for a container format , the Open Packaging Conventions , and a number of XML-based markup languages for the individual components of an office application package. Office Open XML documents are stored in packages that conform to the Open Packaging Conventions . A package is a ZIP file that contains all components ( parts and items ) of a document.

Parts are the individual components (building blocks) of the content of the document (text, graphics, images, etc.), while items are descriptive metadata that determine how the individual components of the document are to be compiled and presented. Items can be divided into relationship items and content-type items . Relationship items describe how the individual parts are related, i.e. i.e. how the individual components of the document must be put together, while content-type items determine the content-type of the individual components, i. i.e. how the individual components must be represented. Every Office Open XML document consists of a main part and possibly other parts that are referenced by the main part via a relationship item . The structure, name and path (within the ZIP file) of the main part depends on the type of Office Open XML document (word processing document, spreadsheet document, etc.).

The markup languages ​​are

and a number of auxiliary markup languages ​​for custom XML data properties (for storing any XML in a package), file properties, mathematical formulas and bibliographic references.

A minimal Office Open XML word processing document contains in the root directory of the ZIP file an XML file named /[Content_Types Autovermietung.xml and three directories / _rels , / docProps and a directory with the actual document data .

Contents of a minimal Office Open XML word processing document
[Content_Types] .xml file
This file contains a description of the contents of the ZIP file
_rels directory
The dependencies between the individual parts are saved in the _rels directories, in a separate file with the extension .rels for each part. In a word processing document with text and images, for example, the text is stored in the file /word/document.xml and the file /word/_rels/document.xml.rels contains the references to the embedded images. There is always a file /_rels/.rels in which the package relationships are saved and the main part is defined. This file is the first file that is read when it is opened.
docProps directory
The / docProps directory contains in the files core.xml, app.xml and custom.xml various document properties ( metadata ) such as author, storage date etc. according to the Dublin Core standard (ISO 15836: 2003) of the “Dublin Core Metadata Initiative "(DCMI).
Document data directory
The document data directory (for example / word) contains the actual document data. In the case of a word processing document, for example a file document.xml which is structured according to WordprocessingML.

Office MathML (OMML)

Office Open XML uses the XML-based markup language Office MathML (OMML) to describe mathematical formulas.

The following Office MathML example describes the fraction :


Document properties

A metadata example ( docProps / core.xml ) according to the Dublin Core standard:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<cp:coreProperties xmlns:cp=""
  xmlns:dc="" xmlns:dcterms=""
  xmlns:dcmitype="" xmlns:xsi="">
  <dc:title>Office Open XML</dc:title>
  <dc:subject>Aufbau des Dateiformats</dc:subject>
  <cp:keywords>Office Open XML, Metadaten, Dublin Core</cp:keywords>
  <dc:description>Office Open XML verwendet ISO 15836:2003</dc:description>
  <dcterms:created xsi:type="dcterms:W3CDTF">2008-06-19T20:00:00Z</dcterms:created>
  <dcterms:modified xsi:type="dcterms:W3CDTF">2008-06-19T20:42:00Z</dcterms:modified>
  <cp:category>Dateiformat für Dokumente</cp:category>

Practical implementation

Microsoft Office 2007 for Windows and Microsoft Office 2008 for macOS only support the outdated version ECMA-376 1st edition of Office Open XML, which was rejected by the ISO; the ISO standard 29500 is not fully supported. Microsoft Office 2010 for Windows enables read access to files in accordance with ISO standard 29500 for the first time, but the standard is only fully supported in Microsoft Office 2013 for Windows. For older Microsoft Office versions (version 2000 or higher) Microsoft offers a “Compatibility Pack” that enables the non-ISO-compliant format to be read and written.

A number of other programs support Office Open XML formats, with compatibility with the outdated version ECMA-376 1st edition in the foreground in all implementations and not the implementation of the ISO standard.

Other such Office packages with Office Open XML support are SoftMaker Office 2010 (import and export of .docx, import of .xlsx), Corel WordPerfect Office from version X4 (import only), ThinkFree Office from version 3.5, OpenOffice. org from version 3.0 and the spin-offs NeoOffice and LibreOffice . Apple supports Office Open XML files in its office product iWork from version '08 and in TextEdit from Mac OS X 10.5.

The document viewer TextMaker Viewer 2010 can open, display and print Office Open XML files. It also enables these files to be converted into Portable Document Format (PDF). The Gnumeric spreadsheet and the AbiWord word processor offer import and export functions.

In June 2008, an SDK was made available by Microsoft for Office Open XML . It allows the processing, creation, checking and modification of the data. The SDK 1.0 is based on .NET 3.0. Contrary to other messages, no office product is required for use.


Office Open XML has been criticized from various quarters , including the OpenDocument advocates IBM and Sun Microsystems as well as members of the open source movement, who published a list of objections in the GrokDoc Wiki to the inclusion of Office Open XML as an ISO standard have published.

The extent of the specification with over 6000 pages is criticized. Critics assume that only Microsoft can implement the specification in full, while it is practically impossible for manufacturers of competing software to implement the file format completely in their applications.

In addition, Office Open XML does not use the W3C recommendations MathML for the representation of formulas or SVG for the representation of vector graphics, but saves these elements in formats developed by Microsoft.

In addition, the standard contradicts some ISO standards, for example the standard for the representation of date and time or the standard for the abbreviation of language names. It is also stated that Office Open XML as a whole could contradict an existing ISO standard, namely the ISO / IEC 26300: 2006 standard ( OpenDocument ).

Microsoft is putting pressure on politicians to prevent the use of the competing OpenDocument format . If votes do not go as Microsoft wants, all research and social spending in the districts would be suspended.

Web links

Individual evidence

  2. Ecma Office Open XML File Formats Standard - Final draft - 9th of October 2006
  3. ^ The Document Foundation, LibreOffice and OOXML . The Document Foundation . Retrieved December 7, 2018.
  4. ntz trade journal for information and communication technology, VDE-Verlag, issue 3–4 / 2008
  5. ECMA-376 (English)
  6. ^ "Oh-oh-XML" - Digital time bomb in German offices. Retrieved September 16, 2015 .
  7. Stefan Krempl: Microsoft implements OOXML "strict" in Office 2013. In: heise online. Retrieved September 16, 2015 .
  8. a b Publication of ISO / IEC 29500: 2008 , November 19, 2008, English
  9. Katie Bird: ISO and IEC approve OpenDocument OASIS standard for data interoperability of office applications. International Organization for Standardization (ISO), May 8, 2006, accessed December 7, 2018 .
  10. OASIS OpenDocument Technical Committee, OASIS ODF Adoption Committee: ISO / IEC 26300: 2006, Information technology - Open Document Format for Office Applications (OpenDocument) v1.0. In: ISO Standards catalog - 35.240.30 - IT applications in information, documentation and publishing. ISO and IEC, 2006, accessed December 7, 2018 .
  11. Ecma International Standardization of OpenXML File Formats Frequently Asked Questions . Microsoft, 2006 (English)
  12. Office File Formats. Microsoft, 1999, accessed May 8, 2015 .
  13. INFO: Microsoft Excel 2002 and XML . Microsoft Knowledge Base (English)
  14. ^ XML Spreadsheet Reference . Microsoft Developer Network (English)
  15. ^ Bringing the XML Vision to the Desktop with Office 2003 . Microsoft (English)
  16. Ecma International Standardization of OpenXML File Formats Frequently Asked Questions . Microsoft, 2006 (English)
  17. Gary Edwards: Commentary on: "An Antic Disposition: Follow the Leader" (English)
  18. Status Report: TC45 - Ecma Office Open XML File Formats Standard . ( Memento of September 1, 2006 in the Internet Archive ) Ecma International, August 17, 2006 (English)
  19. Ecma International approves Office Open XML standard . Ecma International, Geneva, December 7, 2006
  20. wikileaks-press ( Memento from April 23, 2014 in the Internet Archive ) (PDF, 18 kB) ISO / IEC JTC 1 N 8670 Fast Track Process
  21. Vote closes on draft ISO / IEC DIS 29500 standard. ISO, September 4, 2007, accessed September 30, 2010 .
  22. Opponents of Microsoft's OpenXML for aborting ISO standardization. heise online, September 5, 2007, accessed on September 30, 2010 .
  23. Microsoft receives negative award for OpenXML campaign. heise online, October 2, 2007, accessed on September 30, 2010 .
  24. Microsoft's OOXML document format will probably become an ISO standard. heise online, March 31, 2008, accessed on September 30, 2010 : “According to the Norwegian standardization committee, only two parties are said to have voted for OOXML and 21 against. Nevertheless, the result was ultimately "Yes" for Microsoft's format. "
  25. An open letter from SC 34 participants in the Oslo plenary ( Memento from April 15, 2008 in the Internet Archive )
  26. Four national standards bodies appeal against approval of ISO / IEC DIS 29500 (English)
  27. ISO and IEC members give go ahead on ISO / IEC DIS 29500 , August 15, 2008 (English)
  28. Microsoft Office 2007 Fails OOXML Conformance Tests, Alex Brown Admits, Hopes For the Best .
  30. Publicly Available Standards . ISO (English)
  31. ^ What is Ecma International . Ecma International (English)
  32. Microsoft Covenant Regarding Office 2003 XML Reference Schemas . Microsoft, PDF 74 kB
  33. ^ Standardization and Licensing of Microsoft's Office Open XML Reference Schema .  ( Page no longer available , search in web archivesInfo: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. Baker & McKenzie (English)@1@ 2Template: Dead Link /  
  34. Brian Jones: No license needed to use the Office Open XML formats (English)
  35. ^ Microsoft Open Specification Promise . Microsoft
  36. SFLC warns of Microsoft's patent promise .
  37. Microsoft wants to support the open document format ODF (update). heise online, May 22, 2008, accessed on September 30, 2010 .
  38. ^ Dieter Brors: Office 2008 . In: c't special , 2/2008, Mac, p. 62ff.
  39. OOXML and Office 2007 Conformance: a Smoke Test (English)
  40. Jörg Thoma: ISO: Microsoft lets OOXML standard orphan (update)., April 7, 2010, accessed September 30, 2010 .
  41. ^ Jim Thatcher: New file format options in the new Office. In: Office Next (Gray Knowlton blog). August 13, 2012, accessed March 5, 2013 .
  42. Microsoft Office Compatibility Pack ( Memento of February 4, 2007 in the Internet Archive ) for file formats from Word, Excel and PowerPoint 2007. Microsoft Download Center
  43. Corel WordPerfect Office X4 Standard Edition - Compatible . Corel (English)
  44. What's New in ThinkFree Office v3.5 ( Memento April 10, 2016 in the Internet Archive )
  45. Press release of October 13, 2008 (German)
  46. GNOME Office / Gnumeric - Gnumeric Stable 1.8 Series . GNOME (English)
  47. AbiWord v2.6.0 Release Notes . Abisource (English)
  48. AbiWord v2.6.5 Release Notes . Abisource (English)
  49. First development kit for Open XML from Microsoft. heise online, June 11, 2008, accessed on September 29, 2010 .
  50. Information on the Open XML SDK 2.0 for Microsoft Office. In: msdn. Microsoft Corporation. Retrieved September 29, 2010 .
  51. ↑ Getting started with the Open XML SDK 2.0 for Microsoft Office. In: msdn. Microsoft Corporation. Retrieved September 29, 2010 .
  52. Objections to standardization
  53. Bob Sutor: Is Open XML a one way specification for most people? October 16, 2006, accessed September 29, 2010 .
  54. Is OpenXML now a standard? Free Software Foundation Europe, December 8, 2006, accessed September 29, 2010 .
  55. Office Open XML is an ISO standard (update)., April 1, 2008, accessed on September 29, 2010 .
  56. Ecma 376 contradicts numerous international standards. ( Memento from February 23, 2012 on WebCite ) GrokDoc
  57. ISO / IEC 26300 (OpenDocument Format for Office Applications). ( Memento from February 23, 2012 on WebCite ) GrokDoc