What is MIME type "application/sla"?

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

application/sla denotes the MIME type for the STereoLithography file format. It contains 3D surface geometry data used to describe object forms with small triangles.
It supports both ASCII and binary representations. Binary is common for keeping files compact.

3D Printing: Files carry detailed 3D models for printing processes.
CAD Software: Used to preview and manipulate designs.
Rapid Prototyping: Assists in producing quick, iterative physical models.

Files associated with this MIME type use the STL extension.
For more information, see the article on STL File Format on Wikipedia.

Associated file extensions

.stl

Usage Examples

HTTP Header

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


    Content-Type: application/sla

HTML

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


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

Associated file extensions

.stl

FAQs

What is the application/sla MIME type used for?

This MIME type represents STereoLithography (STL) files, which contain 3D surface geometry used extensively in 3D printing and Computer-Aided Design (CAD). While newer standards sometimes suggest model/stl, application/sla remains a widely used legacy identifier for .stl files.

How do I configure Apache to serve STL files correctly?

To ensure your Apache server sends the correct headers, add the directive AddType application/sla .stl to your .htaccess file or the main httpd.conf. This prevents the server from misidentifying ASCII-based 3D models as generic text files.

How do I add application/sla support to Nginx?

You should modify your mime.types file to include the line application/sla stl;. If you lack access to the global configuration, you can add types { application/sla stl; } inside the specific server or location block of your Nginx configuration.

Why do browsers download application/sla files instead of displaying them?

Standard web browsers (like Chrome or Firefox) do not natively render 3D geometry formats. To display application/sla content directly in a web page, developers typically use JavaScript libraries like Three.js or specialized WebGL viewers.

Is application/sla the only MIME type for .stl files?

No, you may also encounter model/stl or model/x.stl-binary. Additionally, the .stl extension is sometimes used for Certificate Trust Lists, which use the MIME type application/vnd.ms-pki.stl; however, this is unrelated to 3D printing.

Why is my STL file being detected as text/plain?

STL files can be saved in an ASCII (text) format. If the web server is not explicitly configured with application/sla, it may analyze the file content, recognize it as text, and default to text/plain. Explicit server configuration fixes this issue.

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.