ILSpy

What ILSpy is

ILSpy is free, open-source software for browsing and decompiling .NET assemblies, with desktop versions for Windows, Linux, and macOS. It can decompile assemblies into C#, including whole projects, and open assemblies from disk, NuGet, running processes, or the Global Assembly Cache; GAC access is limited to Windows. Search and navigation cover types, methods, and properties, alongside hyperlinks, bookmarks, base- and derived-type navigation, and an assembly metadata explorer. ILSpy also converts BAML to XAML and supports ReadyToRun binaries for .NET Core. Related tools include Visual Studio support for versions 2022 and 2026, Visual Studio Code extensions, the ilspycmd dotnet tool, PowerShell cmdlets, and NuGet packages. The desktop application can be extended with plugins, and a scripting API is available. ILSpy handles bytecode but not native-code decompilation. The project says it does not collect personally identifiable information, send user files to third-party services, or use application performance monitoring to gather telemetry or metrics. The listed latest release is 11.1, and the software is distributed under the MIT License.

Who it suits

It suits developers who need to inspect or decompile .NET assemblies on Windows, Linux, or macOS. Its integrations and plugins may also suit users working through Visual Studio or command-line tools.

Getting started

1. Open https://github.com/icsharpcode/ILSpy.
2. Choose the desktop app for Windows, Linux, or macOS.
3. Open an assembly from disk, NuGet, or a running process; use the GAC on Windows.
4. Use the Visual Studio, Visual Studio Code, command-line, PowerShell, or NuGet options if they fit your workflow.
5. Explore plugins or the scripting API as needed.

Verdict

ILSpy offers assembly browsing and C# decompilation across desktop platforms, with several developer integrations and extensions. It is free, but it does not handle native-code decompilation.