A dotPeek alternative: Glass.NET, a free .NET decompiler

Looking for a dotPeek alternative? Glass.NET is a free .NET decompiler built on the same ILSpy decompilation engine, wrapped in a navigation-first UI with project export, a detailed assembly-information view and an exposure report — and it runs beyond Windows. JetBrains dotPeek is a genuinely good, free tool, so this is a fair comparison rather than a takedown: here’s where each fits.

What is dotPeek good at?

dotPeek is JetBrains’ free standalone .NET decompiler, and it’s earned its reputation. It’s a mature, polished tool from a company that builds developer tooling for a living, and a lot of .NET developers already have it installed. Its strengths include:

• Solid decompilation to readable C# using JetBrains’ own engine.
• Good navigation — quick symbol search, find usages, and the kind of “go to everything” flow JetBrains users expect.
• Export to project so you can pull decompiled code into a buildable solution.
• Symbol-server features — it can act as a symbol server and generate PDBs, which is handy when debugging third-party code in Visual Studio.
• Free, with no licence required.

If you’re already in the JetBrains ecosystem or on Windows and comfortable with dotPeek, it’s a reasonable default. We’re not pretending otherwise.

Where Glass.NET differs

Glass.NET approaches the same core job — reading and understanding an unfamiliar assembly — with a few different priorities.

• The ILSpy engine, out in the open. Glass is built on ICSharpCode.Decompiler, the same engine behind ILSpy. The C# it produces is accurate and tracks modern language features. This isn’t a “smarter decompiler” claim — the engine is excellent and widely used, and we build on it rather than reinventing it.
• Navigation as the whole point. Go to Definition (F12, plus Ctrl+Click), Find All References (Shift+F12) streaming into a results panel, Go To All (Ctrl+T) fuzzy quick-open across every type and member, call and type hierarchy, navigation history and a namespace ▸ type ▸ member breadcrumb. References resolve from the decompiler’s own syntax tree, so you land on the right symbol, not a text match.
• A full assembly-information view. Select an assembly and see its identity (name, version, culture, public-key token, strong-name status), PE/runtime traits (target framework, architecture, PE format), product attributes, referenced assemblies, embedded resources and metadata statistics — all in one place.
• C# and IL views, code folding, and matching dark and light themes.
• Export to a buildable project, plus assembly compare with a line diff and an exposure report that summarises what a given assembly reveals — useful for checking what an obfuscator actually produced.
• Beyond Windows. Glass is built on a cross-platform UI toolkit, so it isn’t tied to a single OS the way a traditional Windows-only decompiler is.

And like dotPeek, Glass is strictly static analysis — it reads metadata and IL and reconstructs C#; it never runs the assembly it inspects.

How does Glass.NET compare with dotPeek?

A quick side-by-side. Decompiler features move over time, so confirm current specifics on each vendor’s own site — this reflects our understanding at time of writing, not a guarantee.

	Glass.NET	dotPeek
Price	Free	Free
Decompiler engine	ICSharpCode.Decompiler (ILSpy)	JetBrains’ own
Go to Definition / Find References	✓	✓
Go To All (fuzzy quick-open)	✓	✓
Call / type hierarchy	✓	✓
C# and IL views	✓	✓
Export to buildable project	✓	✓
Assembly-information view	✓ (detailed)	Partial
Assembly compare + line diff	✓	—
Exposure report	✓	—
Symbol server / PDB generation	—	✓
Cross-platform (beyond Windows)	✓	Windows-focused
Live debugging	—	—

Where dotPeek may fit better for you

Credibility means naming where the other tool wins. If any of these describe you, dotPeek may be the better pick:

• You want symbol-server / PDB generation. dotPeek can generate PDBs and act as a symbol server so Visual Studio can step into third-party code. Glass is focused on reading and navigating, not feeding a debugger — if the symbol-server workflow is central to you, dotPeek delivers it.
• You’re deep in the JetBrains ecosystem and want a tool that matches ReSharper/Rider muscle memory and conventions.
• You need live debugging of a managed binary. Neither dotPeek nor Glass does that — it’s a different job. The community-maintained dnSpyEx remains the usual choice there.

How should you decide?

Don’t decide on a feature list — decide on your workflow. Both tools are free, so the cost of trying is only your time:

1. Open an assembly you actually work with in each tool.
2. Try the things you do most — jump to a definition, find every caller of a method, quick-open a type by name, read the IL behind a tricky method, export to a project.
3. See which one lets you move through the code without friction.

For most read-and-understand work — inspecting your own binaries, understanding a dependency, checking what an obfuscator produced, security review, or recovering your own lost source — Glass.NET is designed to make navigation feel like reading your own source. (Use any decompiler only on software you have the right to analyze.)

That “checking what an obfuscator produced” case is worth calling out: it’s exactly why Glass pairs well with Nebula.NET. Protect a build, open it in Glass, and confirm for yourself that the names are gone, the control flow is flattened, and the encrypted methods show only a stub — the exposure report makes it a one-click check.

Get Glass.NET

Glass.NET is completely free — no licence, no seats, no sign-up — and actively developed. Download Glass.NET, open an assembly, and press F12. If you want the wider field, we also compare it with ILSpy, dnSpy and dotPeek together. Found a bug or have a feature request? Tell us — we’re building it in the open.