How to hex header inspector — frequently asked questions
- Step 1Drop a file to inspect — Any file type is accepted. The tool reads up to the tier byte limit from the start of the file.
- Step 2Read the hex grid — Each row: left column is the hex offset, centre is 16 bytes in pairs, right is the ASCII equivalent. Dots represent non-printable bytes.
- Step 3Use annotations if available — Common format fields (magic bytes, length fields, format signatures) are highlighted with tooltips explaining what each byte group represents.
Frequently asked questions
How many bytes does each tier show?+
Free: first 256 bytes. Pro: first 1,024 bytes. Developer: first 8,192 bytes. For most magic-byte and header analysis tasks, 1,024 bytes is sufficient.
Does the file get sent anywhere?+
No. Bytes are read into your browser's ArrayBuffer via the FileReader API and processed entirely in-page JavaScript. No network request is made.
Can I copy the hex output?+
Yes. Click the copy button in the toolbar to copy the full hex dump as plain text in xxd format — suitable for pasting into tickets, reports, or Yara rules.
What formats have annotated fields?+
PE/EXE, ELF, PNG, JPEG, PDF, ZIP (and OOXML), GIF, and MP4 (ftyp box) have colour-coded field annotations. Other formats show raw hex without highlights.
Privacy first
Every JAD Security operation runs entirely in your browser. Files, passwords, and PGP private keys never leave your device — verified by zero outbound network requests during processing.