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

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

application/x-compressed is a MIME type that marks binary data bundled and reduced in size by compression. It often signals that a file was first assembled into an archive and then compressed.
This helps store and transfer many files in one package.

Files in the Tape Archive family, such as TAR, may use this MIME type. While not standardized, it is recognized by various applications and systems.

Use Case: Packaging multiple files and directories into one compressed file.
Functionality: Lowers file size and simplifies distribution.
Key Fact: Combines both archiving and compression techniques.

Learn more about file types and their extensions at Filext.com.

Associated file extensions

.tar

Usage Examples

HTTP Header

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


    Content-Type: application/x-compressed

HTML

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


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

Associated file extensions

.tar

FAQs

What is the application/x-compressed MIME type used for?

This MIME type is a generic identifier for binary files that have been reduced in size via compression. It is historically associated with Unix-based archives, such as TAR files, or files compressed with legacy utilities (like .z or .taz).

How do I open a file with the application/x-compressed content type?

Since this type represents a compressed archive, you need software like 7-Zip, WinRAR, or the command-line tar tool on Linux/macOS. If the file lacks an extension, try adding .tar or .z to the filename to help your software recognize it.

Is application/x-compressed a standard MIME type?

No, the x- prefix indicates it is a non-standard or experimental type. While widely recognized by older systems, modern web standards prefer specific types like application/gzip or application/x-tar for better clarity.

How do I configure Apache to serve files as application/x-compressed?

To force this MIME type for specific extensions, add the following line to your .htaccess or httpd.conf file: AddType application/x-compressed .tar .z. Ensure this matches the requirements of the client software consuming the files.

Why does my browser download the file instead of displaying it?

Browsers are not designed to render raw compressed binary data. When a server sends the application/x-compressed header, the browser defaults to downloading the file so the user can open it with a local utility.

What is the difference between application/x-compressed and application/x-tar?

application/x-tar specifically denotes a Tape Archive file, which acts as a container for multiple files. application/x-compressed implies the data is compressed; however, the two are sometimes used interchangeably for .tar files on legacy server configurations.

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.