# dnSpy — .NET Debugger and Assembly Editor

> dnSpy is a debugger and .NET assembly editor that lets you read, edit, and debug .NET and Unity assemblies without source code.

## Install

Save in your project root:

# dnSpy — .NET Debugger and Assembly Editor

## Quick Use
```bash
# Download the latest release from GitHub
# Extract and run dnSpy.exe (Windows only)
dnSpy.exe

# Open an assembly from the command line
dnSpy.exe MyApp.dll

# Debug a running process
dnSpy.exe --pid 1234
```

## Introduction
dnSpy is a .NET debugger and assembly editor that provides a full-featured IDE experience for analyzing, editing, and debugging .NET assemblies without needing the original source code. It is widely used in security research, malware analysis, and game modding.

## What dnSpy Does
- Decompiles .NET assemblies to C#, Visual Basic, or IL
- Provides an integrated debugger for .NET Framework and .NET Core apps
- Allows in-place editing of IL code, metadata, and resources
- Supports searching across loaded assemblies by type, method, or string
- Handles Unity game assemblies and mono-based applications

## Architecture Overview
dnSpy builds on the ILSpy decompiler engine and Roslyn for C# editing, wrapping them in a VS-like shell with a custom debugger that attaches to CLR runtimes. The editor modifies assemblies in-memory using dnlib, a low-level .NET metadata library, and writes changes back to disk without requiring recompilation.

## Self-Hosting & Configuration
- Download pre-built binaries from GitHub Releases (no installer needed)
- Runs on Windows; requires .NET Framework 4.7.2+ for the host app
- Supports debugging both .NET Framework and .NET Core/.NET 5+ apps
- Themes, fonts, and decompiler settings are configurable via the Options menu
- Note: the project is archived; community forks continue development

## Key Features
- Full C# decompilation with syntax highlighting and navigation
- Integrated debugger with breakpoints, watch windows, and call stacks
- Assembly editing: modify IL, add/remove members, change metadata
- Hex editor for raw binary inspection within the same UI
- Plugin architecture for extending functionality

## Comparison with Similar Tools
- **ILSpy** — read-only decompiler; dnSpy adds debugging and editing
- **dotPeek** — JetBrains decompiler with symbol server but no editing
- **JustDecompile** — Telerik decompiler, now discontinued
- **de4dot** — .NET deobfuscator that complements dnSpy for obfuscated assemblies
- **Rider / Visual Studio** — full IDEs that require source code; dnSpy works directly on binaries

## FAQ
**Q: Is dnSpy still maintained?**
A: The original repository is archived, but active community forks such as dnSpyEx continue development with new features and bug fixes.

**Q: Can I use dnSpy on Linux or macOS?**
A: dnSpy is Windows-only. For cross-platform .NET decompilation, ILSpy offers an Avalonia-based UI that runs on Linux and macOS.

**Q: Does dnSpy handle obfuscated assemblies?**
A: It decompiles them as-is. For better results, run a deobfuscator like de4dot first, then open the cleaned assembly in dnSpy.

**Q: Can I save edited assemblies?**
A: Yes. After editing IL or metadata, use File > Save Module to write the modified assembly to disk.

## Sources
- https://github.com/dnSpy/dnSpy
- https://github.com/dnSpyEx/dnSpy

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Source: https://tokrepo.com/en/workflows/asset-3722dd82
Author: AI Open Source