What is MIME type "application/rsd+xml"?

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

application/rsd+xml is a MIME type for XML files that follow the Really Simple Discovery specification.

This format provides a simple way for websites to publish their service information. Instead of manually configuring endpoints, software such as blog editors and feed readers can automatically discover how to interact with a site.

It standardizes the discovery of services like blog APIs.
It helps client applications connect to website features without extra setup.
It often appears on blog and content management platforms to expose remote publishing capabilities.

Files using this MIME type carry the RSD extension. Their XML structure lists details such as API endpoints and preferred protocols.

For more technical background and real-world examples, see Really Simple Discovery.

Associated file extensions

.rsd

Usage Examples

HTTP Header

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


    Content-Type: application/rsd+xml

HTML

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


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

Associated file extensions

.rsd

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.