Hex Viewer / Editor
Browse, search, and edit raw bytes of any file up to 100 MB — with magic-byte detection, pattern highlighting, and direct download of your modified file.
Drop any file to inspect its bytes
Any format · Max 100 MB · Processed entirely in your browser
Or try:
100% Client-Side · No upload · Up to 100 MB
File bytes never leave your machine. The viewer renders only visible rows — even a 100 MB file stays responsive.
How to use the Hex Viewer (5 steps)
- Open a file: Drop any file (up to 100 MB) onto the viewer, paste a hex string, or pick up where you left off with a file loaded in another CTF Lab tool.
- Navigate bytes: Scroll the hex grid. Jump to any offset with Ctrl+G, search with Ctrl+F (hex, text, or regex). Use Page Up/Down or click the offset column.
- Inspect findings: Magic-byte signatures are highlighted automatically. Click any row to inspect bytes in the detail panel — it shows decimal, binary, and ASCII at a glance.
- Edit bytes (optional): Click any byte in the hex or ASCII column to select it, then type two hex digits to overwrite. All edits are tracked as a diff — original file is never changed.
- Export: Download the modified file or copy the selection as hex / C / Python. Export the full dump as a .hexdump.txt for offline analysis.
Frequently Asked Questions
Does this upload my file anywhere?
No. Everything runs in your browser — the file never leaves your machine. The viewer reads bytes locally using the File API.
What is the maximum file size?
100 MB. Files up to 100 MB are handled with a virtualised grid that only renders visible rows, so the page stays responsive even on very large files.
How does editing work?
Each edited byte is stored in an in-memory diff map. The original file is never modified. When you download the result, the tool assembles the output in 4 MB chunks and writes your edits on top.
What search modes are available?
Hex (formal hex parser — '89 50 4E 47'), Text (ASCII 0x20–0x7E projection), and Regex (applied to the ASCII projection). Files larger than 8 MB are searched in a background WebWorker to keep the UI responsive.
What are bookmarks?
Bookmarks pin specific byte offsets so you can jump back to them instantly. They are stored in your browser's localStorage, keyed by filename and size — they persist across sessions.
What does the session handoff do?
If you used the File Type Detector or Strings Analyzer on a file, it is automatically offered here via IndexedDB — no need to re-upload. Session data expires after 30 minutes and is never sent to a server.
What is the CTF hex format shown?
The standard xxd/hexdump -C format: offset (8 hex digits), two groups of 8 bytes, then an ASCII column in pipes. Bytes 0x20–0x7E are shown as characters; everything else is a dot.