REHex

REHex is a free desktop hex editor for inspecting and changing binary data, with analysis features aimed particularly at reverse-engineering work. It is best suited to technical users who need more context than a basic byte view provides, especially when files are very large or require repeatable analysis. Users who need a mobile or browser-based editor should look elsewhere.

Overview

REHex combines low-level editing with tools that help interpret what those bytes represent. It can work with files larger than 1 TB, making it a serious option for large images, dumps, and other inputs that exceed the practical range of many editors. The GPL-2.0 license also makes it suitable for users who prefer open-source software.

Version 0.64.0 is the latest release shown on the download page, dated 2026-04-03. The project welcomes bug reports and suggestions through GitHub issues, giving users a direct route to raise problems or request improvements.

Key features

Inspect and interpret binary data

REHex decodes integer and floating-point values and places machine-code disassembly inline with the file contents. That keeps numerical and code interpretations close to the bytes being examined, which is useful when tracing structures or investigating compiled data. Binary Templates can annotate data automatically, while byte-range highlighting and manual annotation help preserve findings during a longer investigation.

Virtual address mapping adds useful context when file offsets need to be related to memory addresses. Bitmap visualisation provides another way to spot patterns in raw data. Common text encodings, including ASCII, Unicode, and ISO-8859-X, support inspection of embedded text without switching tools.

Edit, compare, and automate

Bit editing and manipulation support changes below the byte level, and checksumming can be applied to complete files or selected ranges. Intel HEX import and export make the editor practical for workflows that use that format.

Side-by-side comparison works on whole files or chosen selections. Comparing a focused range is useful for isolating a change, while whole-file comparison supports broader revision checks. Lua scripting and Lua plugins extend the editor beyond its built-in commands, giving technically inclined users a way to automate recurring operations or add specialized behavior. That extensibility is a strength for engineering workflows, but it is less relevant if you only need occasional manual edits.

Pricing

REHex has one free plan: REHex: free. It is GPL-2.0 licensed and includes packages for Windows, macOS, and Linux. There are no paid tiers, seat charges, usage quotas, renewal terms, or trial period to weigh up. The single plan suits individuals, teams, and organizations that want the full editor without a subscription; users who need a different platform will need another product rather than another REHex tier.

Platforms

Desktop support covers Windows, macOS, and Linux. Downloads include Windows installers and ZIP archives, a macOS DMG, and 32-bit and 64-bit Linux AppImages. Documented distribution packages are available for Debian, Ubuntu, Fedora, Red Hat Enterprise Linux, FreeBSD, and openSUSE, which gives Linux users options beyond the standalone AppImages.

Who it's for

Choose REHex for reverse engineering, binary investigation, firmware or dump analysis, and other work where decoding, disassembly, annotations, address mapping, and comparisons matter. Its support for files above 1 TB is a notable reason to consider it for unusually large inputs, and Lua support rewards users willing to script or extend their workflow.

It is less suitable for people seeking a phone or tablet app, a web editor, or a minimal tool for occasional byte changes. The analysis and extension features are valuable when used, but unnecessary complexity for straightforward text or hex edits.

Pros and cons

Pros

• Deep binary analysis: Numeric decoding, inline disassembly, templates, address mapping, and annotations add context beyond raw bytes.
• Handles very large files: Support for files larger than 1 TB broadens its usefulness for large data sets.
• Flexible comparison: Whole-file and selection-based side-by-side comparison support both broad and targeted checks.
• Extensible and open source: Lua scripting, plugins, and a GPL-2.0 license suit customizable workflows.
• Broad desktop packaging: Windows, macOS, Linux AppImages, and documented distribution packages simplify installation across desktop environments.

Cons

• No mobile or web version: Its platform coverage is limited to desktop operating systems.
• Specialist feature set: Users who only need basic hex or text editing may find the analysis tooling more than they need.

Alternatives

Hex Editors is the broader category to browse when you want to compare several editors rather than select REHex directly.

Pick HexEd.it instead if Android, iOS, or browser access matters; it is free across those platforms as well as desktop systems. BinEd is another free, open-source option with Android and web availability in addition to Linux, macOS, and Windows.

Choose ImHex, Hecate, wxHexEditor, or dhex when a different free hex-editor project better matches your preferred platform or workflow. wxMEdit is worth considering for text, column, and hex editing, but its hex mode supports files up to 32GB, far below REHex's stated large-file capability. Bedrock Viz is the focused choice for Minecraft Bedrock Edition worlds rather than general binary reverse engineering.

Verdict

REHex is the right choice for desktop users who need a free, open-source editor with serious binary analysis, large-file support, comparison, and Lua extensibility. Its main reason to choose it is the combination of interpretation and editing tools in one cross-platform application. Look elsewhere if you need mobile or web access, or if your work only calls for simple hex changes without reverse-engineering-oriented analysis.