What is MIME type "text/x-spreadsheet"?

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

The MIME type text/x-spreadsheet identifies plain text files that are organized in a grid-like (tabular) structure. This format lets a file hold data in rows and columns without complex formatting, making it easy to edit with simple text editors.
It is non-standard and mostly used by specialized tools rather than general-purpose spreadsheet applications.
For example, LTspice uses this format for its symbol files. The file extension ASY indicates a text-based LTspice symbol. This file stores layout details and component data in an easily reworkable format.

Main use: Storing and editing structured, tabular data in plain text.
Key function: Allows simple modification and parsing without the need for proprietary software.
Additional use: Employed by niche tools like LTspice for defining component symbols and schematic information.

For further details on file extensions and similar MIME types, visit Filext.com.

Associated file extensions

.asy

Usage Examples

HTTP Header

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


    Content-Type: text/x-spreadsheet

HTML

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


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

Associated file extensions

.asy

FAQs

What application opens files with the text/x-spreadsheet MIME type?

Since this is a plain text format, you can open these files using any standard text editor like Notepad, TextEdit, or VS Code. However, specific files like LTspice symbols (.asy) are best viewed and edited within the LTspice software to visualize the schematic symbols correctly.

How do I configure Apache to serve .asy files as text/x-spreadsheet?

You need to manually register the MIME type in your .htaccess file or main configuration, as it is not a standard type. Add the line AddType text/x-spreadsheet .asy to ensure the server sends the correct header to the browser.

Is text/x-spreadsheet compatible with Microsoft Excel?

Not natively. While Excel can import text data, it typically relies on text/csv or proprietary binary formats. If you need to serve spreadsheets for web users to open in Excel, you should use CSV or the standard application/vnd.openxmlformats-officedocument.spreadsheetml.sheet MIME type instead.

Why does my browser display the raw file content instead of downloading it?

Browsers are designed to render text/* MIME types directly in the window. If you want to force the user to download the .asy file instead of viewing the raw text, you must configure your server to send the Content-Disposition: attachment header.

What does the 'x-' prefix mean in text/x-spreadsheet?

The x- prefix indicates that this is a non-standard or experimental MIME type. It is not part of the official IANA registry, meaning support varies between applications, and it is primarily used by specific tools like LTspice rather than the general web.

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

You can add the type definition to your mime.types file or inside a specific server block. Use the syntax types { text/x-spreadsheet asy; } and reload Nginx to apply the changes.

Are text/x-spreadsheet files safe to open?

Generally, yes. Because the MIME type starts with text/, the file is interpreted as plain text and cannot execute binary code or macros like a compiled application. However, you should always be cautious of files downloaded from untrusted sources.

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.