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

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

application/x-wacz is a container format for web archive files. It packages a complete web capture—pages, images, scripts, and metadata—into one compressed file.
This MIME type helps preserve online content in its original form. It is used to keep interactive elements and design intact for future viewing.
Files using this MIME type use the WACZ extension. This format is particularly useful in advanced web archiving projects and digital preservation tools. For more technical details, you may visit FileXT.

Associated file extensions

.wacz

Usage Examples

HTTP Header

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


    Content-Type: application/x-wacz

HTML

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


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

Associated file extensions

.wacz

FAQs

How do I open an application/x-wacz file?

You need a specialized web archive player, such as ReplayWeb.page, to view these files. Because application/x-wacz contains complex web captures with scripts and headers, standard media players or text editors cannot display the content correctly.

What is the relationship between .wacz and .zip files?

A .wacz file is technically a standard ZIP container. If you rename the extension from .wacz to .zip, you can extract it to view the internal structure, which typically includes WARC files, a datapackage.json, and index files.

How do I configure Apache to serve WACZ files?

To ensure your Apache server sends the correct headers, add the following line to your .htaccess file or server configuration: AddType application/x-wacz .wacz. This prevents browsers from misinterpreting the file as a generic binary stream.

How do I configure Nginx for application/x-wacz?

Update your mime.types file or the types block in your server configuration. Add the line application/x-wacz wacz; to ensure Nginx serves files with the .wacz extension using the correct MIME type.

What is the difference between WACZ and WARC?

While WARC files store the raw HTTP request and response data, WACZ is a package format that wraps WARC files along with full-text search indexes and page lists. This makes application/x-wacz much faster and easier for tools to load and browse interactively.

Do web browsers support application/x-wacz natively?

No, browsers like Chrome or Firefox do not have built-in support for rendering this MIME type. To view a WACZ file in a browser, the website must embed a JavaScript-based player, or the user must load the file into a web archiving tool.

Why does the MIME type have an 'x-' prefix?

The x- in application/x-wacz indicates that it is a non-standard or experimental subtype not yet registered with IANA. However, it is widely accepted as the standard format for the Webrecorder project and modern web archiving tools.

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.