File mime type checker

Check file MIME type online instantly with this file MIME type checker tool. Upload or paste a file path, and the tool identifies the correct MIME type (Multipurpose Internet Mail Extensions) based on content and headers. Common long-tail use cases include check MIME type of a file online, detect file content type, and verify correct MIME type for uploads.

What is a File MIME Type?

A MIME type is a standardized way of describing a file’s nature and format. For example, an HTML file uses text/html, a JPEG image uses image/jpeg, and a PDF uses application/pdf. Browsers and servers use MIME types to decide how to handle and display files correctly.

Why use a File MIME Type Checker?

• Security: Prevents malicious files disguised with incorrect extensions.
• Accuracy: Confirms that uploaded files match expected formats (e.g., .jpg is really image/jpeg).
• Debugging: Helps developers resolve file upload and content-type issues in web apps.
• Compliance: Ensures correct MIME headers for serving media, APIs, and downloads.

How to use the File MIME Type Checker

1. Upload a file or provide its path/URL.
2. Run the check to analyze headers and file signatures.
3. View results: correct MIME type, extension, and detected file format.

Who should use it?

• Web developers verifying content types for uploads and APIs.
• System administrators securing file servers and email gateways.
• Security analysts detecting mismatched file types in suspicious uploads.
• Students & learners understanding how MIME types control file handling in browsers.

Examples

Detected MIME types

File: index.html → text/html
File: photo.jpg  → image/jpeg
File: script.js  → application/javascript
File: data.csv   → text/csv
File: report.pdf → application/pdf

Sample output for mismatched file

File: virus.jpg
Extension: .jpg
Detected MIME: application/x-msdownload
Warning: File extension does not match detected MIME type.

Best practices

• Don’t trust file extensions alone—always check the actual MIME type.
• Validate uploads to prevent security breaches from spoofed files.
• Set correct headers on servers (Content-Type) to ensure proper rendering.
• Test across formats for media-heavy sites (images, audio, video, documents).

FAQ

What happens if the MIME type is wrong?

The browser or server may fail to display the file correctly, or worse, expose security risks.

Does this tool check based on extension or content?

Both—extensions give hints, but content signatures confirm the true MIME type.

Can it detect uncommon file types?

Yes—beyond common files like images and PDFs, it can identify archives, executables, fonts, and more.