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

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-arj-compressed indicates an archive that has been compressed using the ARJ algorithm. It bundles many files into one package with reduced size and efficient storage.
It is often seen on legacy systems or in specialized software that still supports older compression formats.

File Archiving: Groups multiple files together for easier management.
Data Compression: Reduces the overall size of data to save disk space.
Backup Solutions: Creates compact archives for backup and restoration purposes.
Legacy Support: Maintains compatibility with systems and archives created in earlier computing eras.

Files typically use the extension ARJ to signify this archive format.

Additional details are available on the Wikipedia page on ARJ.

Associated file extensions

.arj

Usage Examples

HTTP Header

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


    Content-Type: application/x-arj-compressed

HTML

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


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

Associated file extensions

.arj

FAQs

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

You need specialized file archiving software to open these files, as most modern operating systems do not support them natively. Popular tools like 7-Zip, WinRAR, or PeaZip can handle the legacy ARJ format and extract the contents.

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

The x- prefix stands for experimental or extension, indicating that application/x-arj-compressed is not a standard type registered with the IANA. It is a vendor-specific or non-standard identifier used to categorize ARJ archives before the standardization of newer formats.

How do I configure Apache to serve ARJ files correctly?

To ensure your Apache server sends the correct headers for ARJ files, add the following line to your .htaccess file or main configuration: AddType application/x-arj-compressed .arj. This tells the server to associate the .arj extension with this specific MIME type.

How do I add support for this MIME type in Nginx?

In your Nginx configuration (usually nginx.conf or mime.types), add the mapping inside the types block. Use the format: application/x-arj-compressed arj;. Remember to reload Nginx after saving the file to apply the changes.

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

Web browsers do not have built-in support for rendering or extracting ARJ archives. Consequently, when a browser encounters application/x-arj-compressed, it defaults to downloading the file so you can open it locally with a compatible desktop application.

Is the application/x-arj-compressed format secure?

The MIME type itself is just a label for a container format, but like any archive (ZIP, RAR), it can contain malicious files. Always scan downloaded archives with antivirus software before extracting them, especially if they originate from untrusted sources.

Are there alternative MIME types for ARJ files?

Yes, while application/x-arj-compressed is common, you might also see application/arj, application/x-arj, or simply application/octet-stream used for these files. However, using the specific x-arj-compressed subtype helps systems identify the compression method more accurately.

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.