What is MIME type "application/x-mimearchive"?

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-mimearchive marks files that store an entire HTML page and its associated resources in one package.
This format bundles the original HTML, images, style sheets, and scripts into a single file for easier sharing and offline viewing.
Files of this type are often saved with the extensions MHT or MHTML.

Preservation: Ensures all page elements are contained together.
Sharing: Simplifies distribution of complete web pages as one file.
Archiving: Provides a snapshot of the page for future reference.

It uses a multi-part message format to embed various components within a single file.
The "x-" prefix indicates it is a non-standard type, common in many applications even without formal registration.
For more on MIME types, see MDN Web Docs on MIME types.

Associated file extensions

.mht, .mhtml

Usage Examples

HTTP Header

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


    Content-Type: application/x-mimearchive

HTML

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


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

Associated file extensions

.mht, .mhtml

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.