What is MIME type "application/onenote"?

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

application/onenote is the MIME type used by Microsoft OneNote files. It tells systems that a file holds note data created by OneNote. This type lets programs know how to open, display, or share the content.

Files using this MIME type include formats like ONEPKG, ONETOC2, ONETMP, and ONETOC. These file types may serve different roles within OneNote, such as bundling content, holding a table of contents, or managing temporary data.

Note Storage: They store text, images, sketches, and multimedia elements in a digital notebook.
Content Organization: They retain navigation structures like tables of contents and section links for easy access.
Interoperability: They work seamlessly with other Microsoft Office apps and web-based services.
Collaboration: They facilitate sharing and synchronizing notes across devices and users.

For further technical details, visit the official IANA MIME Media Type listing or check Microsoft’s documentation on OneNote file formats.

Associated file extensions

.onepkg, .onetoc2, .onetmp, .onetoc

Usage Examples

HTTP Header

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


    Content-Type: application/onenote

HTML

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


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

Associated file extensions

.onepkg, .onetoc2, .onetmp, .onetoc

FAQs

Which file extensions are associated with application/onenote?

This MIME type is primarily used for Microsoft OneNote files, including .one (sections), .onetoc2 (table of contents), and packages like onepkg. It also covers temporary files such as .onetmp created during editing sessions.

How do I configure IIS to serve OneNote files correctly?

To serve these files on Microsoft IIS, you must add a MIME map in your web.config file or via IIS Manager. Add an entry mapping extensions like .one, .onetoc2, and .onepkg to application/onenote to prevent 404 errors.

Can web browsers display application/onenote files directly?

No, standard web browsers (Chrome, Firefox, Edge) cannot render application/onenote content natively. When a user clicks a link with this MIME type, the browser will usually download the file or attempt to launch the desktop OneNote application.

How do I add support for OneNote files in Apache?

You can enable support by editing your .htaccess file or main configuration. Add the line AddType application/onenote .one .onetoc2 .onepkg to ensure the server sends the correct headers for downloads.

What is the difference between a .one file and a .onepkg file?

A .one file typically represents a single section of a notebook. A .onepkg file is a compressed package (similar to a ZIP) that bundles multiple sections and the onetoc2 index file together for easier sharing or archiving.

Why does my server return a 404 error when downloading OneNote files?

Many web servers do not have the application/onenote MIME type configured by default. If the server does not recognize the file extension (like .onetoc2), it may block the request for security reasons until you manually register the type.

Are there security risks associated with application/onenote files?

Yes, like other Microsoft Office formats, OneNote files can potentially contain embedded scripts or malicious objects. It is important to only open .onepkg or .one files from trusted sources.

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.