ILSpy
What it is
ILSpy is a free, open-source browser and decompiler for .NET assemblies, with a desktop interface for Windows, Linux, and macOS. Built on Avalonia, it can decompile assemblies to C#, including whole projects. Assemblies can be opened from disk, NuGet, running processes, or the Global Assembly Cache, though GAC access is limited to Windows. Search and navigation tools cover types, methods, and properties, alongside hyperlinks, bookmarks, base- and derived-type navigation, and an assembly metadata explorer. ILSpy also includes BAML-to-XAML decompilation and support for ReadyToRun binaries for .NET Core. Related tools include Visual Studio 2022/2026 support, Visual Studio Code extensions, the ilspycmd dotnet tool, PowerShell cmdlets, and NuGet packages. The desktop app supports plugins, and a scripting API is available. ILSpy handles bytecode but not native-code decompilation. Its listed plan costs nothing and uses the MIT License. The project says it does not collect personally identifiable information, send user files to third-party services, or use application performance monitoring for telemetry or metrics. The releases page lists version 11.1 as the latest release.
For and against
For
- Decompiles C# and whole projects.
- Opens assemblies from several sources.
- Includes metadata, search, and navigation tools.
- Desktop app supports plugins.
- Free under the MIT License.
Against
- Does not decompile native code.
- GAC support is limited to Windows.
The verdict
ILSpy provides .NET assembly inspection and decompilation across three desktop platforms, with several development-tool integrations. It is not suited to native-code decompilation, and GAC access is Windows-only.
Who it suits
ILSpy suits developers who need to inspect or decompile .NET assemblies on Windows, Linux, or macOS. It also offers integrations for Visual Studio, Visual Studio Code, and command-line use.
Plans and prices
ILSpy
Open-source software · MIT License
Read 4 Oct 2026 · github.com
On the record
- Additional formats
- ILSpy includes a BAML-to-XAML decompiler and support for ReadyToRun binaries for .NET Core.github.com · read 4 Oct 2026
- Assembly sources
- It can open assemblies from disk, the NuGet feed, running processes, and the GAC, with GAC support limited to Windows.github.com · read 4 Oct 2026
- C# decompilation
- ILSpy decompiles assemblies to C# and supports whole-project decompilation.github.com · read 4 Oct 2026
- Desktop platforms
- The desktop UI runs on Windows, Linux, and macOS and is built on Avalonia.github.com · read 4 Oct 2026
- Extensibility
- The desktop application can be extended with plugins.github.com · read 4 Oct 2026
- Integrations
- Frontends and related tools include Visual Studio 2022/2026 support, Visual Studio Code extensions, the ilspycmd dotnet tool, PowerShell cmdlets, and NuGet packages.github.com · read 4 Oct 2026
- Navigation and metadata
- Features include searching types, methods, and properties; hyperlink navigation; bookmarks; base and derived type navigation; and an assembly metadata explorer.github.com · read 4 Oct 2026
- Privacy
- ILSpy says it does not collect personally identifiable information, send user files to third-party services, or use an application performance monitoring service to collect telemetry or metrics.github.com · read 4 Oct 2026
- Purpose
- ILSpy is an open-source, cross-platform .NET assembly browser and decompiler.github.com · read 4 Oct 2026
- Release
- The GitHub releases page lists ILSpy 11.1 as the latest release.github.com · read 4 Oct 2026
- Security reporting
- The project asks that suspected security issues be reported privately by email and says it cannot guarantee a response time, though it strives to respond within one business day.github.com · read 4 Oct 2026
- Supported versions
- The security policy supports the latest released version and the latest preview or release-candidate version.github.com · read 4 Oct 2026
