SharePoint Designer file
File type: Various data file
A .spdesignasmx file is a SharePoint Designer file associated with Microsoft Office SharePoint Designer.
It is used with SharePoint site design and editing tasks in the Windows application.
File type category:
Various data file
Date updated: September 27, 2026
The SPDESIGNASMX file extension is related to Microsoft Office SharePoint Designer, a specialized HTML editor and web design program used to create and modify Microsoft SharePoint sites and web pages.
The file belongs to the SharePoint Designer environment rather than to a general-purpose document format. Its contents are intended for use by SharePoint Designer when working with SharePoint site design information.
SharePoint Designer is a legacy Windows application, and the format is not commonly used by current web-design software.
Open a .spdesignasmx file on Windows with Microsoft Office SharePoint Designer, the application associated with this format. If the file does not open by double-clicking it, start SharePoint Designer and use its Open command.
Other web editors and standard text editors are not expected to interpret the file correctly.
Open a .spdesignasmx file in Microsoft Office SharePoint Designer and use the application's SharePoint site-management or export features where applicable.
Software applications that handle other tasks involving spdesignasmx files:
Microsoft Windows
Language
