dnSpy for Windows

What this program is for

DnSpy is a free, portable utility for examining and modifying .NET assemblies. It bundles tools that help developers inspect compiled code, step through execution, and make direct edits without a formal installation — simply extract the package and run the executable.

Main capabilities

• Decompilation engine to convert compiled assemblies back into readable source-like code.
• Integrated debugging tools for setting breakpoints and tracing program flow.
• An assembly editor that lets you modify IL and metadata.
• A hex/byte viewer for low-level inspection of binary contents.

Interface and workflow

When launched, DnSpy presents a polished, multi-pane interface with menus across the top and several configurable panels. The central area is dominated by a configuration section where you can adjust preferences for the decompiler, debugger, hex editor, and other modules. Theme options (light/dark) and display settings are available to tailor the environment.

A smaller panel, typically the Assembly Explorer, shows a tree view of the loaded assembly. From there you can navigate namespaces, types, and members to inspect or edit code.

Loading assemblies

You can load an assembly in two common ways:

• Open a file directly from your computer using the file dialog.
• Browse entries from the Global Assembly Cache (GAC) via the Open menu to select a referenced assembly.

Extensibility and target users

DnSpy supports extensions, allowing developers to add custom functionality, but creating add-ons generally requires advanced technical knowledge. The tool is highly capable for experienced developers who need to reverse-engineer or patch .NET binaries. Beginners may find the array of options and settings overwhelming at first.

Alternatives to consider

• Spices.Decompiler — a lightweight decompilation option that some users prefer for simple inspection tasks.
• CFF Explorer — a comprehensive PE editor frequently recommended for detailed binary analysis.
• ILSpy — an open-source decompiler that offers a familiar, straightforward interface for many .NET developers.