ByteScope

Hex Editor

View and edit binary files in your browser — hex, decimal or binary, vim-style.

Your files never leave your browser — all processing is local.

Drop any file here

binary, executable, image, anything — opened locally, never uploaded · handles very large files

About this tool

This online hex editor opens any file and shows it the classic way — an offset column, the bytes, and a synced ASCII column — on a dark, focused editing screen. Switch the byte display between hexadecimal, decimal and binary, adjust how many bytes show per row, and read any value straight out of the data inspector, which decodes the bytes at the cursor as every common integer and float type in both endiannesses.

It's built to handle large files: bytes are streamed from disk in small chunks as you scroll, and edits live in a sparse overlay so nothing is copied until you export. Navigation and editing are vim-style — hjkl to move, i to edit, : to jump to an offset — and it all runs locally, so your file is never uploaded.

Frequently asked questions

Is my file uploaded anywhere?
No. The file is read directly from disk in your browser using the File API — it never leaves your device. Large files are read in 64 KB chunks on demand, so even multi-hundred-megabyte files open instantly without being uploaded or fully loaded into memory.
Can it open very large files?
Yes. The editor uses virtual scrolling and reads only the bytes currently on screen via Blob.slice(), so file size is limited by disk, not RAM. Edits are stored as a sparse overlay on top of the original, so editing a byte in a 1 GB file doesn't copy the file.
What are the keyboard shortcuts?
Navigation is vim-style: h/j/k/l or arrow keys move the cursor, 0 and $ jump to row start/end, g and G jump to the top and bottom of the file, and : opens go-to-offset. Press i to enter overwrite-edit mode and type hex digits; Esc leaves it. v starts a selection, u undoes, and Ctrl/Cmd+Z and Ctrl/Cmd+Shift+Z undo/redo.
Can I show bytes in binary or decimal instead of hex?
Yes — switch the data column between HEX, DEC and BIN. Binary view makes it a bit-level viewer for flags and packed fields, decimal is handy for byte tables, and hex is the classic view with a synced ASCII column alongside.
What does the data inspector show?
It interprets the bytes at the cursor as int8/16/32/64, unsigned variants, float32/64 in both little- and big-endian, plus binary, octal and the UTF-8 code point. It's the quick way to read a value out of a binary structure without doing the conversion by hand.
How do I save my edits?
Click export (or the toolbar's export button). Edited bytes are spliced into runs sliced straight from the original file, so the download is produced without loading the whole file into memory, and unedited files are returned untouched.