AnyTool
Your files never leave your device. All processing happens locally in your browser.

How do I view and edit a file's bytes (hex) online?

Drop any file into AnyTool's hex editor and it shows a classic hex + ASCII dump with an offset gutter. Double-click a byte to overtype it in hex or ASCII, with edited bytes highlighted and full undo/redo. Search hex or text, jump to any offset, and a data inspector decodes the bytes at the cursor as int, uint, and float in little- or big-endian. Save the edited file when done — everything runs in your browser, so your file never leaves your device.

  • Hex + ASCII dump with an offset gutter, synced selection across all three columns
  • Edit bytes in hex or ASCII with edited-byte highlighting and full undo/redo
  • Search hex patterns or text, find next/previous, and go to any offset (decimal or 0x)
  • Data inspector decodes int8/16/32/64, uint, and float32/64 in little- or big-endian at the cursor
  • Large files stay smooth via row virtualization; save the edited file back to disk
  • 100% client-side — your file never leaves your browser, no upload, no size cap, free, no signup

What is

Hex Editor

A hex editor displays a file's raw bytes as hexadecimal alongside an ASCII view so you can inspect and edit binary data directly. AnyTool's reads the file in the browser, shows a hex + ASCII dump with an offset gutter, and lets you edit bytes, search, go to an offset, decode values with a data inspector, and save — all client-side.

Developer Tools

Related terms

Hex ViewerBinary EditorHex DumpData InspectorByte Offset

How to View and Edit a File in Hex

Open a file, edit its bytes in a hex + ASCII dump, and save the result entirely in your browser.

30 secWeb browser
  1. 1

    Open the file

    Drop or choose any file; it loads into a hex + ASCII dump with an offset gutter, read locally and never uploaded.

  2. 2

    Inspect or edit

    Search hex or text, go to an offset, read the data inspector at the cursor, or double-click a byte to overtype it in hex or ASCII.

  3. 3

    Save

    Use undo/redo as needed, then save the edited file back to disk with its original filename.

Result: An inspected or edited file saved back to your device

Frequently Asked Questions

Yes — it is completely free with no signup, no account, and no limits.

The hex editor is 100% free with no account, subscription, or paid tier. You can open, view, edit, search, and save as many files as you want — unlike HHD's Hex Editor Neo web tier, which is a teaser that funnels you to a paid native app.

No — your file is read in your browser and is never uploaded to any server.

Your file is read locally with the browser's FileReader into an ArrayBuffer and never sent to a server — there is no backend and no runtime CDN. Many "online" hex editors historically POST files server-side; AnyTool makes zero-upload an explicit, provable promise, so it works offline and keeps private data private.

No hard cap — large files stay responsive because only the visible rows are rendered.

There is no hard size cap like FreeWWW's 20 MB or DevToolbox's 1 MB display limit. AnyTool virtualizes the row list so only the visible rows are rendered, keeping multi-megabyte files smooth; the practical ceiling is your device's available memory, since the file is held in RAM.

Yes — overtype bytes in hex or ASCII with undo/redo, then save the edited file.

Unlike view-only dumpers, you can double-click a byte and overtype it in either the hex or ASCII pane; edited bytes are highlighted and a full undo/redo stack tracks every change. When you are done, the edited buffer is re-serialized and downloaded as a Blob, preserving the original filename and extension.

Detailed Explanation

Methodology

How the File Hex Editor Works

AnyTool reads the dropped file locally with FileReader into an ArrayBuffer and renders it as a classic 16-bytes-per-row hex + ASCII dump: an 8-digit offset gutter, grouped hex pairs, and an ASCII pane where non-printable bytes show as dots, with selection synced across all three columns. Double-clicking a byte lets you overtype it a nibble at a time in the hex pane or a character at a time in the ASCII pane; edited bytes are highlighted and a full undo/redo stack records every {offset, oldByte, newByte} change. A search box finds hex patterns or text with find-next/previous, a go-to field jumps to any decimal or 0x offset, and a data inspector decodes the bytes at the cursor as int8/16/32/64, uint8/16/32/64, and float32/64 using a native DataView with a little-endian/big-endian toggle plus an ASCII/UTF-8 preview. The row list is virtualized so only the visible rows render, keeping large files responsive, and saving re-serializes the edited buffer into a Blob downloaded under the original filename. Everything runs client-side with no server and no runtime CDN.

  • Hex + ASCII dump with an offset gutter and selection synced across all three columns
  • Byte editing in hex or ASCII with edited-byte highlighting and full undo/redo
  • Hex pattern and text search (find next/previous) plus go to any decimal or 0x offset
  • Data inspector decodes int/uint/float in little- or big-endian via a native DataView at the cursor
  • Row virtualization keeps large files smooth; save re-serializes the buffer to a Blob download
Privacy & Security

Privacy and Offline Use

Reading, viewing, editing, searching, inspecting, and saving all happen in the browser with no runtime CDN, so your file never leaves the device — unlike "online" hex editors that historically POST files server-side or funnel to a paid native app. The file is read with FileReader into an ArrayBuffer in RAM and the edited buffer is downloaded directly as a Blob, so there is no upload and no backend round-trip. There is no hard size cap like FreeWWW's 20 MB or DevToolbox's 1 MB display limit; row virtualization keeps multi-megabyte files responsive, with the practical ceiling set by device memory. The tool works offline after first load and has no signup or paid tier, making it suitable for sensitive or proprietary binaries.

File hex editor: AnyTool vs typical online hex editors
CapabilityAnyToolTypical hex editors
Edit + save (not view-only)Yes (hex + ASCII, undo/redo)Many are view/convert-only
Large filesRow virtualization, no hard capOften capped (e.g. 1–20 MB)
Data inspector at cursorYes (int/uint/float, LE/BE)Often missing
File leaves deviceNo (read in browser)Some upload or funnel to native
Signup / paid tierNoneOften teaser-to-paid funnel

Capabilities reflect the live AnyTool tool; competitor behavior varies by service.