Open-source alternatives to Bytecode Viewer

Recaf is a suite of specialized tools for assembling, editing, deobfuscating, decompiling, and instrumenting Java bytecode and runtime processes. It provides a coordinated environment for modifying compiled Java class files and analyzing the behavior of Java applications. The project distinguishes itself through a multi-level abstraction layer that allows for editing across different formats and a pluggable framework that routes bytecode through multiple configurable decompilation engines. It includes an embedded scripting engine and plugin architecture to automate repetitive tasks and extend

dnSpy is a specialized toolset for the reverse engineering, analysis, and modification of compiled .NET binaries. It functions as a decompiler that converts assemblies back into readable high-level source code, an assembly editor for modifying bytecode and metadata, and a debugger for inspecting compiled binaries. The project integrates a hex editor specifically for inspecting and modifying raw bytes and Common Intermediate Language structures. It allows for the direct modification of binary contents to change application behavior without requiring the original project source files. The tool

ILSpy is a .NET decompiler and binary analyzer designed to convert compiled .NET assemblies back into readable C# source code. It functions as a metadata explorer and a common intermediate language viewer, enabling the analysis of compiled code and the execution of reverse engineering workflows. The project distinguishes itself through specialized translation capabilities, such as converting compiled binary XML (BAML) back into human-readable XAML for user interface analysis. It also provides tools for inspecting native machine code and extracting metadata from program database (PDB) files.

Frida is a dynamic binary instrumentation toolkit that provides a framework for deep process introspection and live application state manipulation. It enables the injection of custom scripts into running processes to trace function calls, modify memory, and analyze application behavior in real-time across diverse operating systems and processor architectures. The project distinguishes itself by embedding a high-performance JavaScript engine directly within the target process, allowing for the execution of user-defined logic for real-time inspection. It utilizes instruction-level hooking to re

Jadx is a comprehensive Java decompilation suite designed to transform compiled binary application files into readable source code. It functions as a static analysis workbench, providing a graphical interface for navigating, searching, and inspecting the internal logic of complex software packages. By utilizing a bytecode-to-Java pipeline, the project reconstructs high-level logical structures from low-level binary instructions, making it a primary tool for Android application reverse engineering. The project distinguishes itself through a sophisticated control flow reconstruction engine and

Luyten is an open source Java decompiler and bytecode analyzer designed to transform compiled class files back into high-level source code. It functions as a graphical user interface for the Procyon decompilation engine, allowing for the inspection and recovery of program logic from Java bytecode. The tool provides capabilities for Java reverse engineering and legacy code analysis, enabling the examination of third-party applications or libraries when original source code is unavailable. The system includes a desktop interface for browsing class hierarchies, recursive classpath scanning to

dnSpy is a specialized suite of tools for the reverse engineering of .NET assemblies, functioning as a decompiler, assembly editor, and debugger. It translates compiled intermediate language back into high-level source code and provides an execution environment for stepping through compiled binaries to inspect runtime state without the original source files. The project includes a BAML decompiler that converts binary application markup language into a disassembled format and translates it into extensible markup language for user interface analysis. It also functions as a binary analysis tool

Arthas is a Java diagnostic tool and runtime debugger designed for real-time troubleshooting of applications. It functions as a remote diagnostics agent that allows users to inspect the runtime state of a Java process, including its heap objects and classloader hierarchies, without requiring a process restart. The project distinguishes itself through advanced bytecode manipulation capabilities, enabling live class hotswapping and the modification of bytecode in running processes. It supports in-memory source compilation and runtime bytecode decompilation to verify and update logic instantly w

Fernflower is a Java bytecode decompiler and reverse engineering tool. It transforms compiled Java class files back into human-readable Java source code to reconstruct original program logic and variable names. The tool functions as a command line bytecode processor capable of batch processing Java archives and class files. It specifically handles obfuscated code analysis by renaming ambiguous identifiers and resolving naming conflicts to make the resulting source code easier to follow. The system employs static analysis to convert bytecode to source, utilizing debug information extraction t

apk-mitm is a command-line utility designed to modify Android APK files to enable HTTPS traffic inspection via a proxy. It functions as a network security patcher and certificate pinning bypass tool, automating the process of altering application packages to allow man-in-the-middle traffic analysis. The tool modifies compiled Android packages by unpacking them, altering internal files, and re-encoding the binary. It specifically focuses on disabling certificate pinning and injecting network security configurations into the application manifest, which permits the use of proxy certificates on b

Apkstudio is a reverse engineering integrated development environment designed for decompiling, modifying, and recompiling Android application packages. It provides a specialized suite for transforming binary files into readable source code and bundling them back into installable application archives. The project features a framework integration system that imports manufacturer-specific files to ensure accurate decompilation of vendor-modified applications. It includes a dedicated editor for Smali, Java, and XML files with syntax highlighting, as well as a hex editor for the direct modificati

radare2 is a reverse engineering framework and binary analysis toolset. It functions as a multi-architecture disassembler, low-level binary debugger, and hexadecimal editor for inspecting executable structures and interpreting machine code when original source files are unavailable. The framework provides capabilities for decompiling machine instructions, performing symbolic analysis, and diffing binary files to identify structural changes across versions. It also includes a digital forensic analyzer and disk analyzer for browsing filesystem formats in userland. The toolset supports binary p

JPEX Software is a comprehensive reverse engineering suite for SWF binary files, serving as an ActionScript decompiler and editor. It provides a toolkit for decompiling, analyzing, and modifying the internal structure of compiled Flash content, including the extraction of scripts and media assets. The project is distinguished by its ability to perform direct binary modification, allowing users to edit bytecode and replace embedded resources without reverting to high-level source code. It includes a runtime ActionScript bytecode debugger for variable inspection and call stack analysis, as well

Cutter is a binary analysis platform and graphical user interface for the Rizin reverse engineering framework. It provides an environment for analyzing the internal logic and data structures of compiled binaries through integrated disassembly and visualization. The platform supports a containerized deployment model to provide isolated environments for binary analysis, which is used to examine suspicious binaries without risking the host system. It is an extensible security tool that allows for the addition of custom analysis capabilities and visualizers via native plugins and scripts. The to

Reverse engineering and pentesting for Android applications

Apktool is an Android APK reverse engineering tool designed to decode application packages into human-readable form and rebuild them after modification. It functions as a Dalvik bytecode disassembler and a resource decoder, transforming binary Android XML and DEX files into editable text and Smali representation. The project serves as an application rebuilder, packing modified resources and Smali code back into a functional Android application package. This capability enables the modification of application logic and resources for testing and deployment. The tool covers a broad surface of an

Krakatau provides an assembler and disassembler for Java bytecode, which allows you to convert binary classfiles to a human readable text format, make changes, and convert it back to a classfile, even for obfuscated code. You can also create your own classfiles from scratch by writing bytecode…

iRET The iOS Reverse Engineering Toolkit is a toolkit designed to automate many of the common tasks associated with iOS penetration testing. It automates a many common tasks including:

Simplify is an Android virtual machine sandbox, bytecode execution tracer, and static analysis framework. It serves as a Dalvik bytecode deobfuscator designed to recover readable code from binaries by simulating program behavior without a physical device. The project distinguishes itself by using execution graph analysis to resolve reflection calls and simplify obfuscated code through constant propagation and dead code removal. It employs multi-path execution simulation to track all possible conditional branch outcomes and maps instruction flow to identify constant values. The system covers

gdsdecomp is a project recovery suite and game engine reverse engineering toolset. It functions as a bytecode decompiler, binary resource converter, and asset extraction tool designed to reconstruct original directory hierarchies and scripts from compiled binary game assets. The toolset specializes in GDScript bytecode decompilation and compilation, translating compiled bytecode back into human-readable source code or converting source code into executable bytecode for specific engine versions and commit hashes. It includes a game archive patcher to modify project archives by replacing intern

This project is a command-line utility and development framework designed to modify, extend, and customize the Spotify desktop client. It functions as a binary patching engine that injects custom scripts, stylesheets, and interface components directly into the host application, enabling users to alter visual themes and add new functionality. The tool distinguishes itself by providing a comprehensive development environment for building modular extensions and custom applications. It includes a hot-reloading pipeline for rapid iteration, a declarative library for constructing interactive UI pan

Psychson is a toolset for modifying USB firmware binaries and flashing custom images to specific hardware controller architectures. It provides utilities for dumping, patching, and flashing custom firmware specifically for Phison 2251-03 USB controllers. The software includes a payload injector for embedding HID keystroke scripts into USB firmware to automate inputs on a target machine. It also features a controller flasher for writing modified burner images directly to Phison-based USB hardware. The suite covers firmware management and hardware forensic analysis, including capabilities for

N64Recomp is a static recompiler and binary-to-C translator designed to convert Nintendo 64 machine code and MIPS architecture binaries into C source code. This system functions as a game console decompiler that enables the native execution of legacy binaries on modern platforms by eliminating the need for runtime interpreters. The project distinguishes itself by translating specialized RSP microcode into executable source code to replace traditional microcode emulation. It employs a system of relocation macros and lookup tables to resolve relocatable memory overlays and dynamic program secti

Unlocker is a patching tool designed to enable the installation and booting of macOS guest operating systems on non-Apple hardware. It functions as a macOS guest enabler by modifying virtualization software binaries to bypass hardware restrictions and support OS combinations that are not supported by default. The project provides a mechanism to emulate Apple-specific device signatures by intercepting calls between the virtual machine manager and the hardware. It also includes a driver image provider that delivers ISO images containing the necessary utilities and drivers for guest installation

AndFix is a binary patching framework and update system for Android applications. It provides tools for generating binary diffs and applying runtime method replacements to fix bugs without requiring a full application update. The system utilizes a binary diff generator to isolate minimal code changes between package versions. It supports the consolidation of multiple incremental patches into a single update file and employs native hooks to replace specific method implementations in memory during the application initialization phase. The framework covers capabilities for binary patch generati

Auto-unlocker is a collection of utilities designed to modify virtualization software libraries to bypass system restrictions on guest operating systems. It primarily functions as a binary patcher that enables the selection and booting of macOS guests within VMware. The project modifies core system libraries to unlock hidden operating system selection options and bypass boot checks for unsupported guests. It also includes a guest tools installer that downloads and applies the driver packages necessary for hardware integration and performance. The toolset provides capabilities for managing vi

SpotX is a desktop client patcher designed to modify the Spotify application. It functions as an ad-blocking modifier and UI customizer that removes advertisements and promotional content from the music player. The project includes tools to disable automatic updates, ensuring that custom patches and visual themes remain active. It also provides a telemetry blocking patch to prevent the application from sending usage data and analytics to the service provider. The tool enables interface customization to hide specific sections, such as podcasts and audiobooks, from the homepage. These modifica