MIME Types Reference

What are MIME Types?

MIME types (Multipurpose Internet Mail Extensions) are standardized labels that identify the type of data contained in a file or being transmitted over the internet. They tell web servers, browsers, and email clients how to process and display content. Every file extension has an associated MIME type that describes its format and purpose.

For example, application/json identifies JSON files, image/png identifies PNG images, and text/html identifies HTML documents. MIME types are essential for web APIs, file uploads, content negotiation, and server configuration.

How to Use This Tool

Search: Enter a file extension (with or without the dot) or a MIME type name to find matches instantly.

Filter: Use the category dropdown to narrow results to specific file types: Text, Image, Audio, Video, Application, or Multipart.

View Details: Click any row to expand full details including description, usage context, and category information.

Copy: Use the copy button to quickly add MIME types to your clipboard for use in code, configuration files, or documentation.

Common Use Cases

• Web Development: Set correct Content-Type headers in HTTP responses to ensure browsers display files correctly.
• API Development: Define request/response formats in REST APIs and specify accepted file types for uploads.
• Server Configuration: Configure web servers (.htaccess, nginx.conf) to serve files with appropriate MIME types.
• File Validation: Validate uploaded files against allowed MIME types to improve security and prevent invalid uploads.
• Documentation: Reference correct MIME types in technical documentation and API specifications.
• Email Systems: Ensure email attachments are processed correctly by specifying proper MIME type encoding.

Frequently Asked Questions

What’s the difference between file extension and MIME type?

File extensions are labels at the end of filenames (.pdf, .jpg), while MIME types are standardized identifiers that describe file content (application/pdf, image/jpeg). Extensions are human-readable; MIME types are machine-readable and used by systems to determine how to process files.

Can one file extension have multiple MIME types?

Generally, no. However, some file types may be served with slightly different MIME types depending on context. For example, JSON files are typically served as application/json, but some legacy systems use text/json. Always use the standard MIME type for consistency.

How do I set MIME types on my web server?

For Apache, add type mappings to .htaccess: AddType application/json .json. For Nginx, edit nginx.conf and add to the types block. For Node.js/Express, use middleware like express.static() which handles MIME types automatically, or set headers manually: res.type(‘application/json’).

What does “application” category mean in MIME types?

The “application” category covers executable, document, and structured data files that require specific applications or processing logic. Examples include PDFs (application/pdf), executables (application/octet-stream), JSON (application/json), and compressed files (application/zip). It’s the broadest category for non-text, non-media files.

Why is correct MIME type important for file uploads?

Correct MIME types ensure security by allowing servers to validate file types, prevent malicious uploads, and enforce user permissions. They also help browsers display files appropriately and enable proper error handling. Always validate both MIME type and file extension on the server side.

What’s the MIME type for plain text files?

Plain text files (.txt) use the MIME type text/plain. You can also specify the character encoding: text/plain; charset=utf-8. Always specify UTF-8 encoding for modern web applications unless using legacy encodings.