MIME Type Lookup

What is MIME Type Lookup?

MIME Type Lookup resolves file extensions to their registered IANA media types and vice versa, covering over 1,500 registered types across text, application, image, audio, video, font, and multipart categories. It provides the full type string (e.g., application/vnd.openxmlformats-officedocument.spreadsheetml.sheet for .xlsx), common aliases, and the recommended Content-Type header value including charset parameters for text types. The tool also identifies whether a type is binary or text-based and suggests appropriate Content-Disposition headers.

Backend developers configuring file upload APIs, DevOps engineers setting up web server MIME type mappings, and email developers constructing multipart messages. The tool runs entirely in your browser — your data never leaves your device.

How to Use MIME Type Lookup

1. Enter a file extension (.pdf, .xlsx, .wasm) or a MIME type string (application/json)
2. View the resolved MIME type, common aliases, and binary/text classification
3. Copy the recommended Content-Type header value with charset parameter if applicable
4. Browse the full registry by category to discover related types

Common Use Cases

• Looking up the correct Content-Type header for file upload endpoints in REST APIs
• Identifying the MIME type needed for static file serving configuration in Nginx or Apache
• Determining whether an unknown file extension corresponds to a binary or text format
• Configuring email attachment MIME types for multipart email construction

Pro Tips

• Always include charset=utf-8 for text MIME types (text/html, text/css, application/json) — omitting it causes browsers to guess encoding, which breaks non-ASCII characters on some systems
• The application/octet-stream type is the catch-all for unknown binary files — servers default to it when the extension is not recognized, which forces browsers to download rather than display
• Some extensions map to multiple MIME types — .js can be application/javascript (standard) or text/javascript (deprecated but still common); use application/javascript for modern configurations

Why Use This Tool?

• Privacy-first: All processing happens locally in your browser. No data is transmitted to any server.
• No installation required: Works in any modern browser on desktop or mobile.
• Completely free: No account, no credit card, no usage caps.
• Fast and reliable: Powered by modern Web APIs for near-instant results.

Related Concepts

Learn more about related topics: Content-Type header, IANA media types, File extension, Content-Disposition.

Frequently Asked Questions