What is MIME type "application/x-osu-beatmap-archive"?

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

application/x-osu-beatmap-archive designates a custom archive format. It packages game audio, images, and map data into one file.

This MIME type lets the osu! game client recognize and extract all necessary beatmap components at once. It works like a compressed container that groups related files together. Using this format improves download speed and simplifies distribution.

Centralized packaging: Bundles all beatmap assets for direct use by the game.
Efficient distribution: Reduces file size and speeds up transfers.
Automatic recognition: The osu! client detects this type to properly install beatmaps.

Files with this MIME type use an archive extension such as OSZ. For more on osu! and its beatmap archives, visit osu!.

Associated file extensions

.osz

Usage Examples

HTTP Header

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


    Content-Type: application/x-osu-beatmap-archive

HTML

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


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

Associated file extensions

.osz

FAQs

How do I open a file with the application/x-osu-beatmap-archive MIME type?

You need to have the osu! game client installed on your computer. Once installed, simply double-clicking the osz file will automatically import the beatmap, audio, and background images into the game.

Why did my beatmap download as a .zip file instead of .osz?

This often happens if the hosting server is not configured to serve application/x-osu-beatmap-archive correctly, causing the browser to interpret the file as a generic ZIP archive. You can fix this by manually renaming the file extension from .zip to .osz and importing it normally.

How do I configure Apache to serve osu! beatmaps correctly?

To prevent browsers from renaming the file or treating it as text, add the specific MIME type to your .htaccess file or server configuration. Use the directive: AddType application/x-osu-beatmap-archive .osz.

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

You should update your mime.types file or the types block in your server configuration. Add the line application/x-osu-beatmap-archive osz; to ensure the correct Content-Type header is sent to users.

Is application/x-osu-beatmap-archive the same as a ZIP file?

Technically, yes; it is a standard compressed ZIP container with a custom extension. If you need to inspect the contents (such as extracting the background image or MP3), you can rename the file extension to .zip and open it with any standard archive tool.

Can I manually create an application/x-osu-beatmap-archive file?

While you can manually zip files and change the extension, it is recommended to use the Export feature within the osu! game editor. This ensures the beatmap metadata is valid and the file structure meets the requirements for the application/x-osu-beatmap-archive type.

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.