OllyDbg is described as '32-bit assembler level analysing debugger. Emphasis on binary code analysis makes it particularly useful in cases where source is unavailable' and is a popular Decompiler in the development category. There are more than 10 alternatives to OllyDbg for a variety of platforms, including Windows, Linux, Mac, BSD and Haiku apps. The best OllyDbg alternative is x64dbg, which is both free and Open Source. Other great apps like OllyDbg are Ghidra, IDA, GNU Project Debugger and radare.
x64dbg is a 64-bit assembler-level debugger for Windows. The corresponding 32-bit debugger is called x32dbg.
Almost everyone thinks x64dbg is a great OllyDbg alternative.
Ghidra is a software reverse engineering (SRE) framework created and maintained by the National Security Agency Research Directorate. This framework includes a suite of full-featured, high-end software analysis tools that enable users to analyze compiled code on a variety of...
IDA delivers robust disassembly and decompilation, supporting diverse processors and file formats. Its high-quality pseudocode mirrors original source code, aiding analysis of multi-platform software. It features dynamic debugging, metadata control with Lumina, and effective code deobfuscation.
GNU Project Debugger, or gdb, is a command-line, source-level debugger for programs that were written in C, C++, D, Objective-C, Fortran, Java, Pascal, assembly, Modula-2, or Ada and compiled for any of a number of different target architectures including x86, x86-64, IA-64...
Radare, the highly featured reverse engineering framework. NOTE: it is better to use the "radare 2", not the "radare".
Features
Multi-architecture and multi-platform GNU/Linux, Android, *BSD, OSX, iPhoneOS, Windows{32,64} and Solaris i808.
Rizin is a feature rich reverse engineering framework in development, focusing on stability and high code quality, a welcoming and curious community culture and implementation of cutting edge binary analysis research.
Cutter goal is to be an advanced FREE and open-source reverse-engineering platform while keeping the user experience at mind. Cutter is created by reverse engineers for reverse engineers.
Radare project started as a forensics tool, a scriptable commandline hexadecimal editor able to open disk files, but later support for analyzing binaries, disassembling code, debugging programs, attaching to remote gdb servers, ...
Hopper is a reverse engineering tool for OS X and Linux, that lets you disassemble, and decompile your 32/64bits Intel Mac, Linux, Windows and iOS executables!
Immunity Debugger is a powerful new way to write exploits, analyze malware, and reverse engineer binary files. It builds on a solid user interface with function graphing, the industrys first heap analysis tool built specifically for heap creation, and a large and well supported...
REDasm is a cross platform disassembler with a modern codebase useful from the hobbyist to the professional reverse engineer.
United States
Belgium
EU
Japan
Spain
It's open source and has all the features you would expect, and it will work with both 64b and 32b software perfectly!