How to Use the File MIME Type & Magic Bytes Checker
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1
Drag and drop any file or browse from your device.
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2
View the detected magic number signatures (hex bytes).
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3
Compare file extension with true underlying MIME type to identify disguised or spoofed files.
Practical Example & Use Case
Common Real-World Scenario
Checking whether a file named "report.pdf" is truly a PDF document or a renamed executable file (.exe / .zip).
Technical Notes & Limitations
Browser Engine Architecture
Reads the first 32 header bytes locally via FileReader. 100% private.
Frequently Asked Questions
How does it detect file type without relying on extension?
It inspects the initial byte signature (magic numbers) defined by file format specifications (e.g. 25 50 44 46 for PDF).