Drop files hereor click to choose. Several files at once are fine. Only the first 64 KB of each file is read, and nothing leaves your browser.
Inspect bytes manually

Paste a hex dump or a hex string (the output of xxd or hexdump -C works as-is).

How it works

Most file formats start with a fixed byte sequence called a signature or "magic number". A PNG begins with 89 50 4E 47, a PDF with %PDF, a ZIP with PK. This tool reads only the first 64 KB of each file, compares it against a database of known signatures, and then looks inside container formats to tell a DOCX from a JAR, a WebP from a WAV, or an MP4 from a HEIC.

  • Detects images, video, audio, archives, documents, executables, fonts and databases
  • Looks inside ZIP, RIFF, ISO-BMFF (MP4/MOV/HEIF), EBML and PE/ELF containers
  • Recognises text formats such as JSON, XML, SVG, HTML, CSV, YAML, PEM and scripts
  • Flags files whose extension does not match their content
  • Shows dimensions, versions, architectures and other embedded facts where available
  • Privacy-friendly: files never leave your browser