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

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

MIME Type: application/x-fictionbook+xml tags files that store e-books in a structured XML format. It breaks a book into clear parts—such as text, chapters, and metadata—making it easy for software to read and process the content.

Files using this type are mainly digital books. For example, formats like FB2 and FB3 rely on it.

Main use: Display and exchange of e-books.
Structure: Leverages XML to separate text, styling, and metadata.
Interoperability: Eases conversion to other digital book formats.
Functionality: Supports reading applications and conversion tools by providing a clear document layout.

For more details, see the FictionBook documentation.

Associated file extensions

.fb2, .fb3

Usage Examples

HTTP Header

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


    Content-Type: application/x-fictionbook+xml

HTML

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


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

Associated file extensions

.fb2, .fb3

FAQs

What file extensions use the application/x-fictionbook+xml MIME type?

This MIME type is primarily associated with .fb2 and .fb3 files. These are FictionBook e-book files that store content in a structured XML format, distinct from binary formats like PDF.

How do I configure Apache to serve FictionBook files?

To ensure browsers and e-readers recognize the file correctly, add the media type to your .htaccess file or global configuration. Use the following line: AddType application/x-fictionbook+xml .fb2 .fb3.

How do I add support for .fb2 files in Nginx?

You can add the MIME type definition inside your mime.types file or within a specific location block. The configuration syntax is: types { application/x-fictionbook+xml fb2 fb3; }.

Why does my web browser show code instead of a book when opening this file?

Most browsers do not have native rendering engines for application/x-fictionbook+xml. Because the format is based on XML, the browser displays the raw document tree (tags and data) rather than formatted text. You need an e-book reader extension or standalone software to view it as a book.

What is the difference between application/x-fictionbook+xml and application/epub+zip?

FictionBook (.fb2) consists of a single XML file that defines the semantic structure of the book. In contrast, EPUB is a ZIP archive containing multiple HTML files, CSS styles, and images.

What software can open application/x-fictionbook+xml files?

Popular e-book management software like Calibre, FBReader, and CoolReader handle this MIME type natively. These programs parse the XML tags to apply proper formatting, chapters, and metadata for the reader.

What does the 'x-' prefix mean in this MIME type?

The x- prefix indicates that application/x-fictionbook+xml is a non-standard or private subtype that was not officially registered with the IANA when it was created. Despite this, it is the widely accepted standard for identifying FictionBook files.

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.