Microsoft Office uses the XML-based file formats, such as.docx,.xlsx, and.pptx. These formats and file name extensions apply to Microsoft Word, Microsoft Excel, and Microsoft PowerPoint.

Office Open XML (also informally known as OOXML) is a zipped, XML -based file format developed by Microsoft for representing spreadsheets, charts, presentations and word processing documents. Ecma International standardized the initial version as ECMA-376. ISO and IEC standardized later versions as ISO/IEC 29500.

The Office Open XML File Formats specification is an open, international, ECMA-376, 5th Edition and ISO/IEC 29500 standard. The Open XML file formats are useful for developers because they are an open standard and are based on well-known technologies: ZIP and XML.

The Office Open XML file formats are a set of file formats that can be used to represent electronic office documents. There are formats for word processing documents, spreadsheets and presentations as well as specific formats for material such as mathematical formulas, graphics, bibliographies etc.

The Open XML format (.docx/.xlsx/.pptx) is the default format in all supported versions of Microsoft Office and, unless you have a specific reason to use a different format, it's the format we recommend using for your Office files.

The Open XML SDK simplifies the task of manipulating Open XML packages and the underlying Open XML schema elements within a package. The classes in the Open XML SDK encapsulate many common tasks that developers perform on Open XML packages, so that you can perform complex operations with just a few lines of code.

Open XML is designed to faithfully represent existing word-processing documents, presentations, and spreadsheets that are encoded in binary formats defined by Microsoft Office applications.

Office Open XML, also known as OpenXML or OOXML, is an XML-based format for office documents, including word processing documents, spreadsheets, presentations, as well as charts, diagrams, shapes, and other graphical material. The specification was developed by Microsoft and adopted by ECMA International as ECMA-376 in 2006.

This is a comparison of the Office Open XML document file format with the OpenDocument file format.