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

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

The MIME type application/x-ms-reader is specific to digital book files used by the Microsoft Reader application.
It indicates that the file contains structured e-book content and tells systems how to handle it correctly, especially when opening or transferring files over the web.
Files with this MIME type are most commonly seen as LIT documents.

File association: It signals operating systems and browsers to launch the right application (Microsoft Reader) for proper viewing.
Content rendering: It supports the display of formatted text, images, and metadata, ensuring the digital book looks as intended.
Legacy support: It remains important for accessing older e-book libraries created for Microsoft Reader.

The x-ms- prefix shows that this is a vendor-specific or experimental format. For more on MIME types, check out MIME on Wikipedia.

Associated file extensions

.lit

Usage Examples

HTTP Header

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


    Content-Type: application/x-ms-reader

HTML

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


    <a href="file.dat" type="application/x-ms-reader">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-reader');
      res.end('Content here');
    }).listen(3000);

Associated file extensions

.lit

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.