What is MIME type "application/x-dtbncx+xml"?

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

application/x-dtbncx+xml is a custom MIME type for a navigation file used in Digital Talking Books.
It defines the structure of a book's table of contents in an XML format. This file guides assistive software to jump between chapters, sections, or topics.

Navigation Control: Maps out the book’s content and hierarchy.
XML-based Structure: Uses XML to define navigation points clearly.
Accessibility: Helps visually impaired users and those with reading difficulties navigate digital books.
Integration with Multimedia: Often used with related file types such as WAV, XML, MP4, MP3, and OPF.

The primary file that uses this MIME type is the NCX file. Its role is central in the Digital Talking Book standard for guiding the reading or listening experience through an organized set of navigation points.
For more technical details, see related documentation on digital book standards through external resources such as DAISY Consortium.

Associated file extensions

.wav, .xml, .mp4, .mp3, .opf, .ncx

Usage Examples

HTTP Header

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


    Content-Type: application/x-dtbncx+xml

HTML

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


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

Associated file extensions

.wav, .xml, .mp4, .mp3, .opf, .ncx

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.