Help:Hex editor

A hex editor

A hex editor is possibly the most multi-purpose and general tool used in ROM hacking. It displays the ROM data as a hexadecimal string, which allows one to examine it, provided they have knowledge of the game's internals.

Most hex editors support character tables (or thingy tables, as per the widely used hex editor thingy and later thingy32), which are small plaintext .tbl files that link every hexadecimal value with a character, which proves most useful when reading and changing text data. Some text editors allow relative searching for strings and automatic creation of tables.

List of Useful Hex Editors

Standalone program

Paid

• 010 Editor - One of the best hex editors out there. Features include histograms, search with wildcards in binary and text mode, color highlighting, common binary data types shown, resynchronizing file comparisons, checksum and hashing algorithms, and most notably scriptable binary templates for custom structures with optional and variable-size parts, open drives and process memory.
• Hex Workshop - A fairly good hex editor with some advanced features, such as character distribution, search by bit masks, support for custom character tables (only 8 bit values can be mapped), color highlighting of structured data and interpretation in structure viewer, common binary data types shown, checksum and hashing algorithms, resynchronizing file comparisons, open drives. Be warned, v6.0.1 doesn't work under Japanese locale.

Free

• MadEdit - A very useful Text Editor and Hex Editor combo for Windows, Linux and BSD. The best thing about it is that it supports many popular text encodings such as Unicode (UTF-8, UTF-16/32 LE/BE), Big5, GBK, EUC, S-JIS, etc. (Discontinued.)
  • MadEdit-Mod - A continuation of MadEdit with more features added. BSD version not available.
• ImHex - A very powerful FOSS Windows, macOS, and Linux hex editor with support for advanced features like "patterns", which are similar to 010 Editor's "Binary Templates" and allow you to be able to write a parser script that displays values in the file with color highlighting of the data, and shows them in a nested list.
• GNU poke - An extensible hex editor for GNU. Uses its own file format called pickle (a C-like programming language with templates) to analyze file formats.
• HxD - A very compact hex editor only 900kB big! Features include opening hard drives, RAM and disk images, basic file comparison, checksum and hashing algorithms. Handles basic text file encodings as well.
• Thingy32 - The infamous hex editor originally written by Necrosaro and then ported over to MS Visual Basic. With it came the option to use two table files at the same time and the actual table format, nowadays sometimes known as thingy tables as mentioned above. Can only use table files encoded in current locale. Has problems with multi-byte locales, such as CJK.
• Windhex32 - Allows usage of table files (specialized support for Japanese characters), relative search, built-in table editor and graphics editor (which sucks, though).
• XVI32 - One of the more compact hex editors (less than 1MB download), and capable of viewing CP437, ISO 8859-1, and ASCII encoded text.
• 0xED - A native Mac OS X hex editor based on the Cocoa framework. Lightweight, intuitive, and user-friendly, but lacks advanced features.

Web-based

• hexed.it - A very useful online hex editor.