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MIME Type
font/otf
FontMIME type for OpenType font files.
MIME type reference, HTTP example, browser usage, common mistakes, and related content.
What is the font/otf MIME type?
The MIME type font/otf is used to tell browsers, APIs, and servers how a file or response body should be interpreted.
MIME stands for Multipurpose Internet Mail Extensions, and MIME types are now a standard part of HTTP responses and web content delivery.
When a browser or client receives a response with font/otf, it uses that information to decide how the content should be processed, rendered, downloaded, or executed.
Example
Content-Type: font/otf
HTTP example
HTTP/1.1 200 OK Content-Type: font/otf Content-Length: 1256
Common file extensions
.otf
Common use cases
- Custom typography
- Design assets
- Hosted font files
Common mistakes
- Using the wrong MIME type for the file being served
- Returning text/plain instead of font/otf
- Forgetting required parameters like charset when relevant
- Using a deprecated MIME type in older server configurations
- Serving assets with a mismatched Content-Type header, causing browser parsing issues
How browsers use it
Browsers use the Content-Type response header to decide how a response should be handled. For example, HTML is rendered as a page, CSS is parsed as styles, JavaScript is executed as script, and images are displayed visually. If the MIME type is incorrect, the browser may refuse to load the file correctly or may treat it as plain text or a download instead.
Browser support
Supported in modern browsers, though WOFF2 is typically preferred for production web use.
Developer note
Like TTF, it works, but WOFF2 is usually better for web performance.