What is the XSN file format?
.xsn is an archive container format associated with the Microsoft InfoPath software tool. An .xsn file is a CAB archive that contains template data, view formatting, embedded graphics, scripts, and an XML schema bundled into a single deployable package. InfoPath can open and edit .xsn files directly; the archive can also be extracted with any CAB-compatible utility by renaming it to .cab. .xsn files are form template files used for creating structured data-entry documents.
InfoPath is a template management tool for building XML-based electronic forms. Template data is stored in component files inside the archive - primarily a manifest.xsf descriptor, XSL view transforms, an .xsd schema, and optional script assemblies. InfoPath was officially discontinued; the final release is InfoPath 2013, not 2014. As of 2026, Microsoft has blocked new form publishing to SharePoint Online and is retiring InfoPath Forms Services entirely. Microsoft Power Apps and Microsoft Forms are the recommended replacements. User-submitted data is saved as separate .xml files, not inside the .xsn template itself.
Security & safety
RISK: MEDIUMXSN templates can embed script and managed-code "code-behind" that runs when the form is opened or filled, and full-trust InfoPath solutions can access local resources - so an untrusted XSN is not entirely passive. Only open templates from sources you trust, and prefer inspecting an unknown one by renaming to .cab and reading the files rather than loading it in InfoPath. Beware random "XSN viewer/opener" download sites; with InfoPath retired they are often adware - use 7-Zip plus a text editor instead.
Format details
in a nutshellPrograms that open XSN files
Windows3 apps
7-Zip
Open-source Rename the copy .xsn -> .cab (or open directly) and extract to read manifest.xsf, XSL and schema as plain text. 
Microsoft InfoPath 2013
Paid Open in InfoPath Designer to edit the template, or InfoPath Filler to fill it in. Discontinued - only works if already installed (no longer sold).
Any text/XML editor (after extraction)
Open-source Open the extracted .xsf/.xsl/.xsd files in Notepad++ or VS Code to inspect the form's logic. Technical details
deep spec| Container format | Microsoft Cabinet (CAB) archive |
| Magic bytes | 4D 53 43 46 ("MSCF") at byte offset 0 - identical to any .cab file |
| MIME type | application/vnd.ms-infopath |
| Compression | MSZIP (DEFLATE) applied per-folder within the CAB container |
| Byte order | Little-endian (inherited from CAB specification) |
| Internal encoding | Binary outer container; internal XML, XSL, and XSD files are UTF-8 text |
| Core internal file | manifest.xsf - the form definition manifest declaring views, schema, and trust level |
| Schema versioning | solutionFormatVersion attribute in manifest.xsf distinguishes InfoPath 2003, 2007, 2010, and 2013 schemas |
| Integrity and signing | Per-folder CAB data checksums; full-trust solutions may carry Authenticode code signatures |
| Typical file size | 10 KB - 2 MB |
| Platform | Windows only |
| User data format | Submitted data saved as separate .xml files bound to the template, not embedded in the .xsn |
| Trust levels | Restricted, Domain, or Full Trust - declared in manifest.xsf; Full Trust requires signing or administrator deployment |
| Extraction method | Rename to .cab to open with any Cabinet tool (e.g., 7-Zip); internal files are human-readable XML/XSL |
| Superseded by | Microsoft Power Apps, Microsoft Forms, and SharePoint list forms (Microsoft's official replacements) |
| Released | 2003 (Microsoft Office InfoPath 2003) |
| Latest version | InfoPath 2013 (last release; no version after Office 2013) |
| Specification | learn.microsoft.com |
XSN conversions
Community Q&A
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