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

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

text/x-dart is a MIME type that signals a file contains Dart source code. It tells editors and servers to treat the file as plain text with Dart-specific syntax.

Main use: Identify Dart source code so that code editors and IDEs can offer proper syntax highlighting and code analysis.
Practical usage: It helps web servers serve these files as text rather than binary.
Technical note: The x- prefix indicates a non-standard type often used during development.

Files using this type include the Dart file format such as DART.

For more on Dart and its applications, visit Dart’s official site.

Associated file extensions

.dart

Usage Examples

HTTP Header

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


    Content-Type: text/x-dart

HTML

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


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

Associated file extensions

.dart

FAQs

What is the purpose of the text/x-dart MIME type?

The text/x-dart MIME type identifies a file as Dart source code, typically associated with the .dart extension. It informs web servers and text editors that the content is plain text containing logic written in the Dart programming language.

Do web browsers execute text/x-dart files natively?

No, modern web browsers do not execute Dart code directly. To run Dart applications on the web, the code is compiled to JavaScript (served as application/javascript); the legacy "Dartium" browser that ran Dart natively is no longer supported.

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

To ensure Apache serves Dart files with the correct content type, add the following line to your .htaccess file or main configuration: AddType text/x-dart .dart. This prevents the browser from guessing the file type incorrectly.

Why does the MIME type start with an 'x-' prefix?

The x- prefix indicates that text/x-dart is a non-standard or experimental subtype. While it is not a strictly standardized IANA media type, it is the convention widely used by developers and tools to identify Dart source text.

What is the difference between text/x-dart and application/dart?

Historically, application/dart was used when the specific intent was execution (e.g., in the Dartium browser). Today, text/x-dart is commonly used to denote the source code itself as a readable text format, similar to how text/x-c is used for C code.

How do I fix 404 errors when requesting .dart files on IIS?

Microsoft IIS blocks unknown file extensions by default for security. To fix this, open the MIME Types feature in IIS Manager and add a new entry with the file extension .dart and the MIME type text/x-dart.

Is it a security risk to serve text/x-dart files publicly?

Yes, if you do not intend to share your source code. Serving raw .dart files exposes your application logic and potential intellectual property; for production web apps, you should generally serve only the compiled JavaScript bundles.

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.