ShadowToolkit

File Type & MIME Detector

Inspect true file types and MIME information locally.

100% In-Browser
100% In-Browser PrivacyLocal

Your files and data are processed locally and never leave your device.

Select any file to inspect

Inspect MIME types, exact file size, and compute cryptographic file hashes

Max size: 600MB •100% In-Browser

What is File Type & MIME Detector?

File Type & Magic Bytes Detector inspects the true binary header signature (magic bytes) of any file to determine its actual format, regardless of incorrect, missing, or spoofed file extensions. It displays exact MIME types, hexadecimal signatures, and associated applications.

Zero-Server Client-Side Guarantee

Unlike legacy online utilities that upload sensitive media and documents to remote cloud storage, Shadow Toolkit executes this entire operation directly within your browser's local runtime. Your raw data never crosses the network.

Key Capabilities

  • Inspects initial binary header bytes (magic numbers) to identify true file formats
  • Detects spoofed or renamed extensions (e.g., an EXE disguised as a JPG)
  • Database of hundreds of binary signatures: Images, Videos, Audio, Archives, Documents, Executables
  • Displays full MIME type, standard file extension, and hex byte dump
  • 100% private client-side binary inspection—files never leave your device

Common Use Cases

1Identifying mystery files that downloaded without a file extension (.tmp or extension-less files)
2Verifying whether a suspicious email attachment is a genuine document or a renamed executable
3Troubleshooting file upload errors caused by incorrect MIME type headers
4Auditing file integrity, validating format extensions, and inspecting binary data structures safely

How to use File Type & MIME Detector

01

Select Any File

Drop the unknown or extension-less file into the inspector.

02

Inspect Magic Bytes

Review the detected true file format, MIME type, and hex header signature.

03

Fix Extension

Rename the file with the verified extension to open it correctly.

04

Export Diagnostic Report

Review the binary inspection headers, verify checksums, and copy the technical report or rename file extensions accordingly.

Frequently Asked Questions

Magic bytes are specific leading byte sequences at the very beginning of a file (e.g. '89 50 4E 47' for PNG) that definitively identify its format to operating systems, independent of file extension.

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