What is MIME type "application/x-ms-manifest"?

A MIME type is a string that tells browsers and other tools how to handle a particular kind of file.

application/x-ms-manifest is a MIME type used by Windows to handle XML-based assembly manifests.
It informs the system about an application's identity, its dependencies, and required privileges. This helps prevent conflicts when multiple versions of libraries are present.
Files with this MIME type typically have the extension MANIFEST.

Main purpose: Define the structure and dependencies of Windows assemblies.
Use case: Enable side-by-side assembly loading to avoid version conflicts.
Use case: Specify security and runtime requirements for applications.

More details can be found in the Microsoft Application Manifests Documentation.

Associated file extensions

.manifest

Usage Examples

HTTP Header

When serving content with this MIME type, set the Content-Type header:


    Content-Type: application/x-ms-manifest

HTML

In HTML, you can specify the MIME type in various elements:


    <a href="file.dat" type="application/x-ms-manifest">Download file</a>

Server-side (Node.js)

Setting the Content-Type header in Node.js:


    const http = require('http');    
    
    http.createServer((req, res) => {    
      res.setHeader('Content-Type', 'application/x-ms-manifest');    
      res.end('Content here');    
    }).listen(3000);

Associated file extensions

.manifest

FAQs

How do I configure IIS to serve .manifest files?

You must manually add the MIME type if it is not present in your IIS configuration. Open IIS Manager, select your site, double-click MIME Types, and add an entry with the extension .manifest and the MIME type application/x-ms-manifest. This is essential for ClickOnce deployments to work correctly.

Why do I get a 404 error when downloading a .manifest file?

This usually happens because the web server (like IIS) is configured to block unknown file extensions for security reasons. If the server does not recognize the .manifest extension, it returns a 404.3 error. Registering application/x-ms-manifest in the server's MIME map resolves this issue.

Is application/x-ms-manifest the same as the PWA manifest?

No, they are distinct standards. application/x-ms-manifest is used for Windows XML manifests (ClickOnce, Side-by-Side assemblies). Progressive Web Apps (PWAs) use the MIME type application/manifest+json for their manifest.json files.

How do I add this MIME type to Apache or Nginx?

For Apache, add the line AddType application/x-ms-manifest .manifest to your .htaccess file. For Nginx, include application/x-ms-manifest manifest; within the types block of your nginx.conf or mime.types file.

Can I open files with this MIME type in a text editor?

Yes, files served as application/x-ms-manifest are standard XML text files. You can view or edit them using Notepad, Visual Studio Code, or any XML-compatible editor to inspect the application's dependencies and security privileges.

What is the relationship between this MIME type and ClickOnce?

ClickOnce relies on this MIME type to identify deployment manifests. When a user clicks a link to a .application or .manifest file, the correct Content-Type header ensures the browser hands the file to the .NET Framework for installation rather than displaying it as text.

General FAQ

What is a MIME type?

A MIME (Multipurpose Internet Mail Extensions) type is a standard that indicates the nature and format of a document, file, or assortment of bytes. MIME types are defined and standardized in IETF's RFC 6838.

MIME types are important because they help browsers and servers understand how to process a file. When a browser receives a file from a server, it uses the MIME type to determine how to display or handle the content, whether it's an image to display, a PDF to open in a viewer, or a video to play.

MIME types consist of a type and a subtype, separated by a slash (e.g., text/html, image/jpeg, application/pdf). Some MIME types also include optional parameters.

How do I find the MIME type for a file?

You can check the file extension or use a file identification tool such as file --mime-type on the command line. Many programming languages also provide libraries to detect MIME types.

Why are multiple MIME types listed for one extension?

Different applications and historical conventions may use alternative MIME identifiers for the same kind of file. Showing them all helps ensure compatibility across systems.