What is MIME type "application/toml"?

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

application/toml identifies configuration files written in the TOML format. It provides a simple way to store settings in a text file.
Developers favor this format because its syntax is clear and concise. Its structure supports nested keys, which helps in organizing configuration data.

Configuration Storage – Hold application settings and preferences.
Human Readability – Files are easy to read and edit manually.
Structured Data – Supports a nested and hierarchical data arrangement.

Files using this MIME type typically have the extension TOML.
For detailed guidance and updates, see the TOML official documentation.

Associated file extensions

.toml

Usage Examples

HTTP Header

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


    Content-Type: application/toml

HTML

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


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

Associated file extensions

.toml

FAQs

Is application/toml the official MIME type for TOML files?

Yes, application/toml is the standard media type registered with IANA for TOML files. While you might occasionally encounter text/toml, you should use application/toml to ensure strict adherence to current web standards and compatibility.

How do I configure Nginx to serve .toml files correctly?

To serve .toml files with the correct Content-Type, add the mapping to your mime.types file or inside the server block. Use the directive application/toml toml; to prevent Nginx from defaulting to a generic binary type.

How do I add TOML support to an Apache web server?

You can enable the correct MIME type by modifying your .htaccess file or the main httpd.conf. Add the line AddType application/toml .toml so that Apache correctly identifies these configuration files when requested by a client.

Why does my browser download TOML files instead of displaying them?

Browsers are not designed to render application/toml natively like they do HTML or images. Because the MIME type is not a standard display format for the web, browsers typically default to downloading the file or displaying it as raw text.

Should I use application/toml or application/json for configuration?

Use application/toml if the file is intended to be read and edited by humans, as it supports comments and a cleaner syntax. Choose application/json if the data is primarily generated and consumed by machines, as JSON is more ubiquitous in API responses.

Are there security risks in serving application/toml files?

Yes, TOML files often contain sensitive configuration data, such as database passwords or API keys. Unless the file is intended for public consumption (like a public manifest), you should configure your server to deny access to these files to prevent information leakage.

How do I open a file sent as application/toml?

Since TOML is a plain text format, you can open it with any text editor like Notepad, VS Code, or Sublime Text. The MIME type simply indicates to the software that the text follows the specific structure defined by the TOML specification.

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.