What is MIME type "application/warc"?

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

application/warc is a MIME type for web archive files. It designates containers that store archived web content, including copies of web pages, images, and metadata.

This format collects entire HTTP exchanges—requests, responses, and headers—to capture a website’s state at a given time. It is essential for digital preservation and research projects that aim to analyze historical versions of web content.

Key uses include:

Web Archiving: Creating detailed snapshots of websites for historical record.
Digital Preservation: Storing data for long-term access and legal compliance.
Data Analysis: Gathering network traffic archives for research and trends analysis.

WARC files are commonly distributed in their standard form as WARC or in a compressed format as WARC.GZ.

For detailed technical specifications, see the WARC File Specifications.

Associated file extensions

.warc, .warc.gz

Usage Examples

HTTP Header

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


    Content-Type: application/warc

HTML

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


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

Associated file extensions

.warc, .warc.gz

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.