File MIME Type Checker
Verify a file's real type from its magic bytes — detects 32 signatures locally and flags renamed or mislabeled files.
What Is the File MIME Type Checker?
The File MIME Type Checker reads the opening bytes of a file — the magic-number signature — and identifies the real format regardless of what the name claims. It detects 32 signatures (images including TIFF-based camera RAW, PDF and PostScript, Photoshop documents, ZIP-family containers, audio, video, DICOM medical images, SQLite databases, executables for Windows and Linux, and fonts), shows the browser-reported MIME type, a hex and ASCII preview, and warns when the bytes contradict the name. Everything runs locally; only the first 136 bytes are read.
How It Works
Drop any file on the target. The detected type, browser-reported type and first bytes appear instantly.
When to Use It
Use it to check a suspicious attachment, debug upload validation, or figure out what a file with a missing or wrong extension really is.
Frequently Asked Questions
- Why Does My DOCX Detect As ZIP?
- Because it genuinely is one — Office files, EPUB books and APK apps are ZIP containers with structured contents inside.
- Is The File Uploaded?
- No. The browser reads 32 bytes from your disk and nothing leaves your device.
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