MIME Types Reference

MIME types reference — Content-Type values for JSON, HTML, images, video, PDF, form data. application/json, text/html, image/png, multipart/form-data. Full reference.

3 min read

What it is

A reference for common MIME types used in web development, email, and file systems.

Installation

This is a reference, no installation required.

Core Concepts

MIME (Multipurpose Internet Mail Extensions) types are standardized ways to identify the format of a file or data. They consist of a type and a subtype, separated by a slash (e.g., text/html).

Commands / Usage

Text Formats

text/plain: For plain text files.
```
echo "This is plain text." > file.txt
```
text/html: For HTML documents.
```
echo "<h1>Hello</h1>" > page.html
```

text/css: For CSS stylesheets.

echo "body { color: blue; }" > style.css

text/javascript or application/javascript: For JavaScript code.
```
echo "console.log('Hello');" > script.js
```

text/xml: For XML documents.

echo "<root><item>value</item></root>" > data.xml

Image Formats

image/jpeg: For JPEG images.
```
# (Assume image.jpg exists)
```
image/png: For PNG images.
```
# (Assume image.png exists)
```
image/gif: For GIF images.
```
# (Assume image.gif exists)
```

image/svg+xml: For SVG vector graphics.

echo "<svg width='100' height='100'><circle cx='50' cy='50' r='40' fill='red'/></svg>" > graphic.svg

Audio and Video Formats

audio/mpeg: For MP3 audio files.
```
# (Assume audio.mp3 exists)
```
audio/ogg: For Ogg Vorbis audio files.
```
# (Assume audio.ogg exists)
```
video/mp4: For MP4 video files.
```
# (Assume video.mp4 exists)
```
video/webm: For WebM video files.
```
# (Assume video.webm exists)
```

Application Formats

application/json: For JSON data.

echo '{"name": "example", "value": 123}' > data.json

application/xml: For XML data (can sometimes overlap with text/xml).
```
echo "<config><setting>on</setting></config>" > config.xml
```
application/pdf: For PDF documents.
```
# (Assume document.pdf exists)
```
application/zip: For ZIP archives.
```
# (Assume archive.zip exists)
```
application/octet-stream: A generic binary file type, often used as a fallback.
```
# (Assume binary_data exists)
```
application/x-www-form-urlencoded: Used for submitting HTML form data.
```
# (Used implicitly by web forms)
```
multipart/form-data: Used for submitting HTML form data that includes files.
```
# (Used implicitly by web forms with file uploads)
```

Other Common Types

image/x-icon: For favicon files.
```
# (Assume favicon.ico exists)
```
font/woff2: For WOFF2 web fonts.
```
# (Assume font.woff2 exists)
```

Common Patterns

Setting Content-Type in curl: When uploading files or sending specific data types.

curl -X POST -H "Content-Type: application/json" --data '{"key": "value"}' http://example.com/api/data
curl -X POST -F "file=@/path/to/your/image.png;type=image/png" http://example.com/upload

Identifying MIME type from a file (using file command):

file --mime-type -b /path/to/your/document.pdf
# Output: application/pdf
file --mime-type -b /path/to/your/image.jpg
# Output: image/jpeg

Gotchas

text/javascript vs. application/javascript: While both are used for JavaScript, application/javascript is the more modern and preferred MIME type according to RFC 6838. Some older systems might still expect text/javascript.
text/xml vs. application/xml: Similar to JavaScript, application/xml is the more general and preferred type for XML. text/xml is often used when the XML is known to be text-based and doesn’t necessarily conform to strict XML parsing rules (though this distinction is often blurred).
application/octet-stream Fallback: Browsers will typically prompt the user to download files with this MIME type, as they don’t know how to render them directly.
Custom MIME Types: You can define custom MIME types using the application/x- prefix, but these are not standardized and should be used with caution, especially for interoperability.