File signature inspector

Peek at a file's leading bytes to detect its real format — PNG, PDF, ZIP, ELF, SQLite and more — and compare with its extension.

Read in this browser. The file never leaves your device.

Only the first 512 bytes are read to match a magic-number signature (PNG, JPEG, PDF, ZIP, MP4, SQLite, ELF, and ~25 more). A detected type means the file starts with the right bytes — it does not prove the file is complete or safe.

How to use

  1. Choose any file.
  2. See the detected signature and the extension verdict.
  3. Check the hex dump of the first bytes.

What it supports

Reads the first 512 bytes in the browser only. Magic-byte detection covers common image, document, archive, media, and executable formats; files without a known signature report as unknown, or as text when the bytes are valid UTF-8. It is not a malware scanner or a content validator.

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