What is MIME type "application/mbox"?

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

application/mbox is a MIME type for storing email messages in one plain‐text file. Each email is saved one after another with its standard headers and body. This format is common when archiving or migrating email data.

Main use: Consolidate emails into a single file for backup or transfer.
Additional use: Importing/exporting mailboxes between clients.
Useful in debugging and maintaining email archives.

Individual messages are often saved as EML files, while complete mail archives use the MBOX or MBX formats.

For further details, see the Mbox Archive Format on Wikipedia.

Associated file extensions

.eml, .mbox, .mbx

Usage Examples

HTTP Header

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


    Content-Type: application/mbox

HTML

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


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

Associated file extensions

.eml, .mbox, .mbx

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.