What is MIME type "application/x-votable+xml"?

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

application/x-votable+xml is an MIME type that signals data in the VOTable format.
It uses an XML structure to represent table data with its metadata and layout. This makes it easy to exchange and process the data with standard XML tools.

Astronomy Data Exchange: It is used to share astronomical catalogs and survey results.
Interoperability: Different software tools can read and process VOTable data.
Data Archiving: It archives structured astronomical data reliably.
Virtual Observatory Projects: It supports large-scale data queries and networked information systems in astronomy.

Files using this MIME type are often saved with the XML or VOT extension.
The format is widely recognized in the astronomical community for its flexible, readable structure.
Learn more about MIME types on the Wikipedia page on Internet media types.

Associated file extensions

.xml, .vot

Usage Examples

HTTP Header

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


    Content-Type: application/x-votable+xml

HTML

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


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

Associated file extensions

.xml, .vot

FAQs

What is the primary purpose of application/x-votable+xml?

This MIME type identifies data formatted according to the VOTable standard, widely used in astronomy for exchanging tabular data. It ensures that software tools developed by the International Virtual Observatory Alliance (IVOA) recognize the file as a specific astronomical dataset rather than generic XML.

How do I configure Apache to serve .vot files correctly?

You should add the MIME type definition to your .htaccess file or main configuration. Add the line AddType application/x-votable+xml .vot to ensure the server sends the correct header. This helps client applications launch the appropriate astronomy software automatically.

Can web browsers display application/x-votable+xml files?

Yes, most modern browsers will render the file as a standard XML tree because of the +xml suffix. However, they will not display a formatted table unless the file includes a reference to an XSLT stylesheet. For data analysis, specialized tools like TOPCAT or Aladin are required.

What is the difference between application/x-votable+xml and text/xml?

While both contain XML data, application/x-votable+xml is more specific and signals that the content adheres to the VOTable schema. Using the specific MIME type allows Virtual Observatory tools to automatically detect and process the astronomical data, whereas text/xml might be treated as a generic document.

Which file extensions are associated with this MIME type?

The specific extension for this format is usually .vot. However, because the format is valid XML, these files are frequently found with the generic .xml extension as well. When checking MIME types, servers usually map .vot explicitly to this type.

Why does this MIME type include an 'x-' prefix?

The x- prefix typically denotes a non-standard or experimental type that has not been registered in the primary IANA tree. Despite this, application/x-votable+xml is the established standard within the astronomical community for identifying VOTable resources.

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

To support this type in Nginx, open your mime.types file (usually located in /etc/nginx/). Add the entry application/x-votable+xml vot; inside the types block, then reload the server to apply the changes.

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.