The XAP file format was developed by Microsoft for their Windows Phone OS (versions 7 and 8). This file format is used by Windows Phone as an executable program file for unpacking and installing third party apps in the device. Also known as application package files, these XAP files contain installer code, libraries, modules and resources that are used by the third party app during the installation and setup process.These XAP files are also known as Microsoft Silverlight installation resource files. These are also used for installing Silverlight apps.These XAP files do not contain human readable data. It's best to only use these XAP files for installing Silverlight apps and third party programs in Windows Phone 7 / 8.
Try a universal file viewer
File.org aims to be the go-to resource for file type- and related software information. We spend countless hours researching various file formats and software that can open, convert, create or otherwise work with those files.
If you have additional information about the XAP file format or software that uses files with the XAP suffix, please do get in touch - we would love hearing from you.