Class Libraries & REST APIs for the developers to manipulate & process Files from Word, Excel, PowerPoint, Visio, PDF, CAD & several other categories in Web, Desktop or Mobile apps. Develop & deploy on Windows, Linux, MacOS & Android platforms....Excel2007 xlsx format workbook . save ( dataDir + "book.out.xlsx" ,... fileFormatType . XLSX ) # Save in SpreadsheetML format workbook...