What is MIME type "audio/x-mod"?

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

audio/x-mod is a MIME type that signals a group of tracker module files. These files hold both sound samples and playback instructions. They let a computer recreate music note by note.

This format is ideal for use in digital music tracking. It was popular with early computing and remains a favorite in retro gaming and chiptune circles.

Module Playback: Players interpret these file instructions and samples to reproduce music exactly as composed.
Compact Composition: The format keeps file sizes small, using patterns rather than storing full audio waveforms.
Creative Flexibility: Musicians can mix and modify samples easily within tracking software.
Wide Compatibility: Many file variants, each tied to different trackers or composers, share this MIME type.

Formats using this MIME type include files like DB (DIGIBooster module), MSO (MedlySound module), CT (CyberTracker 64 chiptune), MUS (MVSTracker Music module), and the well-known MOD format.
Many others—such as XM, IT, ORG, and MO3—are also part of this group.

For deeper technical insight, visit Wikipedia: Module file.

Associated file extensions

.db, .mso, .ct, .mus, .mod, .cpp, .mix, .osp, .stp, .fmt, .smc, .dm, .psa, .dss, .skm, .spm, .sa, .ml, .sng, .omf, .uni, .far, .org, .mo3, .emd, .fc, .as, .ems, .xm, .it, .kt, .mxm, .ast, .ds2, .et, .imf, .dtm, .ft, .bsi, .sap, .uds, .stm, .ftm, .cop, .amf, .amx, .mon, .ss, .psc, .thn, .tfc

Usage Examples

HTTP Header

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


    Content-Type: audio/x-mod

HTML

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


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

Associated file extensions

FAQs

What types of files use the audio/x-mod MIME type?

This MIME type is primarily used for tracker modules, which are music files containing samples and sequencing patterns. Common extensions include .mod, .xm (FastTracker 2), .it (Impulse Tracker), and .s3m.

Do web browsers support audio/x-mod natively?

No, standard browsers like Chrome, Firefox, and Safari do not support module playback via the HTML5 <audio> tag. To play these files on a website, you must implement a JavaScript-based player such as libopenmpt or chiptune2.js.

How do I configure Apache to serve module files correctly?

You can ensure the correct Content-Type is sent by adding this directive to your .htaccess or server config file: AddType audio/x-mod .mod .xm .it .s3m. This helps client applications identify the file format immediately.

Why does my browser download the .mod file instead of playing it?

Because browsers lack native support for audio/x-mod, they treat the file as an unknown binary or generic download. To enable playback, you must embed a specialized web player that can decode the tracker format within the browser.

What is the difference between audio/x-mod and audio/mpeg?

While audio/mpeg (MP3) stores a recorded audio waveform, audio/x-mod stores musical instructions (notes, pitch, effects) and small sound samples. This makes module files significantly smaller and allows for dynamic editing, but they require specific software to render the sound.

How do I set up Nginx to recognize tracker modules?

Open your mime.types file (usually in /etc/nginx/) and add the line: audio/x-mod mod xm it s3m;. After saving, reload Nginx with sudo service nginx reload to apply the changes.

Is audio/x-mod a standard IANA MIME type?

No, the x- prefix indicates that it is a non-standard or experimental type. While it is the de facto standard for the tracking community, it is not officially registered with IANA like audio/wav or audio/ogg.

Can I convert audio/x-mod files to standard audio formats?

Yes, software like OpenMPT (Open ModPlug Tracker) or VLC can render the module's instructions into a standard stream. You can then save the output as audio/wav or audio/mpeg for compatibility with standard media players.

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.