Choose by workflow, not by an assumed accuracy or speed ranking. ILSpy is the clearly documented choice for a cross-platform desktop decompiler; dnSpy is the one to examine when debugging or editing assemblies is central; dotPeek offers Assembly Explorer navigation plus project and PDB generation; and Glass.NET focuses on navigation and assembly inspection. There is no controlled comparison here establishing a universal winner for decompilation quality or performance.
How do the four decompilers differ?
All four can help inspect compiled .NET assemblies, but their documented strengths are not interchangeable. Glass.NET’s maker says it is built on ICSharpCode.Decompiler, the engine also used by ILSpy; that is a first-party description, not an independent test of either product’s output. The feature summaries below reflect the respective project or vendor documentation, not hands-on benchmark results.
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| Tool | Documented fit | Platform or distribution details | Notable output or integration |
|---|---|---|---|
| Glass.NET | Navigation-oriented inspection, including references, symbol search, call and type hierarchies, navigation history, and consolidated assembly information, according to its publisher. | Desktop product; the comparison source does not establish platform compatibility details here. | C# and IL views, project export through the app or glass export, assembly comparison, and an exposure report, according to the publisher. |
| ILSpy | Open-source .NET assembly browsing and decompilation, with search, symbol navigation, metadata exploration, and plugins documented by the project. | Its desktop UI is documented for Windows, Linux, and macOS using Avalonia. | C# and whole-project decompilation; command-line, IDE, PowerShell, and package front ends are also documented. |
| dnSpy | Debugging and editing .NET and Unity assemblies, alongside analysis and decompilation workflows. | Check which repository, fork, or distribution you are using and whether it supports your target runtime. | Documents breakpoints, stepping, C# and Visual Basic editing, IL and metadata editing, analysis, and project export. Its repository states GPLv3. |
| dotPeek | Assembly Explorer browsing, symbol search, declaration and reference navigation, and code or IL inspection. | JetBrains documents installation through dotUltimate or a portable distribution; verify current platform details. | Documents Visual Studio project and PDB generation, type and dependency diagrams, and symbol-server use for debugging. |
Feature lists do not establish that exported projects exactly reproduce original source or will build without changes. Check the current release and target-framework compatibility for the assembly you need to inspect.
Which one should you choose for your task?
You need a desktop app on Windows, Linux, or macOS
Start with ILSpy if cross-platform desktop availability is a requirement: its project explicitly documents a Windows, Linux, and macOS UI. That does not guarantee support for every target assembly or runtime, so verify the current release against your file and environment.
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You need to follow symbols, references, or call relationships
Glass.NET’s publisher emphasizes Go to Definition, Find All References, fuzzy Go To All, call and type hierarchies, a namespace/type/member breadcrumb, and navigation history. dotPeek documents symbol filtering and search, declaration/reference navigation, and hierarchy and dependency diagrams. ILSpy documents search, hyperlinks, bookmarks, and base/derived type navigation. These are useful starting points, not evidence that one tool is faster or more complete on every assembly. Test a representative file and the navigation style you prefer.
You need to debug or edit an assembly
dnSpy is the clearest documented starting point for debugging and editing .NET or Unity assemblies: its repository lists breakpoints, stepping, inspection windows, and editing C#, Visual Basic, IL, and metadata. dotPeek documents symbol-server use for debugging compiled assemblies, but its feature list is not the same as dnSpy’s assembly-editor workflow. With dnSpy, identify the specific maintained repository or distribution and confirm support for the runtime and scenario you need.
You need generated code or debugging artifacts
ILSpy and Glass.NET document project decompilation or export; dnSpy documents project export; dotPeek documents generation of Visual Studio projects and PDBs. Treat these as generated starting points, not recovered originals. Inspect the output and rebuild it in your intended environment before relying on it.
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Glass.NET’s publisher describes a consolidated assembly-information view covering identity, runtime and PE traits, product attributes, references, resources, and metadata statistics. ILSpy documents metadata exploration, while dotPeek’s Assembly Explorer covers assemblies, namespaces, types, members, references, and resources. Glass.NET’s comparative claim that its view is more complete comes from its own maker-authored comparison, not a neutral assessment.
What each tool documents beyond basic C# viewing
Glass.NET
Delta1 Labs describes Glass.NET as a navigation-focused desktop decompiler built on ICSharpCode.Decompiler. Its listed features include C# and IL views, an assembly comparison with line diff, an exposure report, lazy loading, and off-thread decompilation. These are publisher-described capabilities and performance-related claims; they should not be read as independently measured results.
ILSpy
The ILSpy project documents opening assemblies from several sources, searching types, methods, and properties, navigating through links and bookmarks, and exploring metadata. It also lists BAML-to-XAML decompilation, ReadyToRun support, plugins, and multiple front ends. Check the official project documentation and release information for compatibility with your particular target.
dnSpy
The dnSpy repository describes a debugger and .NET assembly editor. Along with debugging and editing, its feature list includes usage analysis, search, and project export. Because the name is used by forks and distributions, use the repository and release page for the specific project you intend to install rather than relying on an unofficial download site.
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dotPeek
JetBrains documents C# display with side-by-side IL, source display when source files are available, symbol filtering and search, and assemblies associated with running processes. Its getting-started page is dated May 16, 2024; verify current product and platform details before choosing it for a new setup.
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What decompilation can—and cannot—tell you
A decompiler reconstructs a readable high-level representation from compiled material; it does not restore the original source exactly. In its Malware Analysis – Windows Tech Notes, version 1.0 dated February 19, 2026, the Scientific Working Group on Digital Evidence explains that C# compiles to Intermediate Language (IL) retaining substantial metadata, which allows tools to translate it back into code. That helps explain why decompilation can support static inspection, but the resulting representation is not proof of how a program behaves when executed.
Static inspection and dynamic analysis answer different questions. Dynamic analysis involves running a sample in a contained environment to observe behavior. Do not execute an unknown or suspicious assembly merely because a decompiler has made its contents readable; use appropriate containment and analysis procedures.
Licensing and practical checks before installing
The project and product sources identify ILSpy as open source, dnSpy’s repository states GPLv3, JetBrains describes dotPeek as free software, and Glass.NET’s publisher says it is free. Those short descriptions do not replace the current license terms or explain every redistribution condition. Check the applicable official source before redistributing, embedding, or using a tool in a context where licensing matters.
Quick Recap
- Confirm the current release supports the target framework and assembly format.
- For dnSpy, verify the exact repository or fork and its release status rather than assuming every distribution with that name is equivalent.
- Try the tool on a representative assembly, especially if navigation, generated output, or debugger integration is essential.
- Review generated code and artifacts; the documented export features do not promise exact source reconstruction.
- Use a contained environment when investigating unknown code that you plan to execute.
Official references
- Delta1 Labs’ Glass.NET comparison (September 17, 2026); product-maker claims should be read as such.
- ILSpy project repository.
- dnSpy repository.
- JetBrains dotPeek getting-started documentation (dated May 16, 2024).
- SWGDE documents; see Malware Analysis – Windows Tech Notes, version 1.0, February 19, 2026.
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