JetBrains dotPeek Download, Features, Setup, and Alternatives
Ever opened a DLL file and wished you could see the code inside? JetBrains dotPeek does exactly that. It is a free .NET decompiler that turns compiled assemblies back into readable C# code.
Developers use it to debug third-party libraries, recover lost source code, and understand how a .NET application really works. In this guide, you will learn how dotPeek works, how to install it, where it falls short, and which tools can replace it.
Quick answer: JetBrains dotPeek is a free Windows tool from JetBrains that decompiles .NET assemblies (.dll, .exe, .winmd) into C#, shows IL code, and exports results to a Visual Studio project.
What Is JetBrains dotPeek?
dotPeek is a standalone .NET decompiler and assembly browser made by JetBrains, the company behind ReSharper, Rider, and RubyMine. It first appeared in 2011 as an early access build, with a stable release in 2012.
It reads compiled .NET files and shows approximate C# source code. You can browse types, jump between methods, and search everything you have loaded. The tool is free, and JetBrains states that no license key is required.
How dotPeek Works as a .NET Decompiler
.NET code does not compile straight to machine code. Your C# becomes Intermediate Language (IL) plus metadata, and the runtime converts that to native code later.
Because IL and metadata keep type names, method signatures, and references, dotPeek can rebuild loops, properties, async methods, and lambdas. The result is close to the original, but not identical, like a book translated from a summary.
Who Should Use JetBrains dotPeek?
dotPeek helps anyone working with .NET code they did not write:
- C# developers checking how a framework or NuGet package behaves.
- Support engineers investigating a bug in a vendor DLL.
- Security researchers doing legitimate code review.
- Teams with lost source code who only have the compiled build.
- Students learning how C# compiles.
What Types of DLL and EXE Files Can dotPeek Open?
dotPeek opens managed .NET files. According to JetBrains, it supports libraries (.dll), executables (.exe), and Windows metadata files (.winmd).
| File Type | Supported? | Notes |
|---|---|---|
| .NET Framework DLL | Yes | Most common use case |
| .NET Framework EXE | Yes | Console and desktop apps |
| .NET (Core) assemblies | Yes | Modern .NET builds |
| .winmd files | Yes | Windows metadata |
| Native C++ DLL | No | Not managed code |
| Obfuscated assemblies | Partly | Output may be messy |
A simple rule: if the file was built from C#, VB.NET, or F# on .NET, dotPeek can usually read it. Native C or C++ files are out.
JetBrains dotPeek Features
dotPeek is more than a “show me the code” button. It borrows many navigation tools from ReSharper, which makes exploring large assemblies much easier.
Decompile .NET Assemblies into C# Code
Open an assembly and dotPeek shows C# you can read, copy, and search. It handles async methods, lambdas, pattern matching, and newer C# constructs.
Practical tip: If a method looks strange, compare the C# view with the IL view. The difference often explains what the compiler did.
Browse DLL Files and Explore .NET Assemblies
The Assembly Explorer lists every loaded assembly with namespaces, types, and members in a tree. You can expand a DLL like a folder and even load assemblies from the local NuGet package cache.
View Intermediate Language (IL) Code
dotPeek can show IL code, the low-level instructions the runtime reads. It helps when decompiled C# looks wrong or when you study compiler behavior. Most users stay in C#, while advanced users switch to IL.
Navigate Classes, Methods, Namespaces, and References
Navigation is where dotPeek shines. Thanks to ReSharper-style features, you can:
- Jump to a type or symbol quickly
- Find usages of a method, property, or variable
- Go to base and derived types
- View a type hierarchy
- Search for strings and attributes
Export Decompiled Code to a Visual Studio Project
You can export a decompiled assembly as a Visual Studio project (.csproj), which helps when rebuilding a legacy library whose source is gone. Expect some cleanup: treat the export as a strong head start, not a finished project.
Generate and Use PDB Files with dotPeek
dotPeek can generate PDB files and act as a symbol server. According to JetBrains documentation, it does not store symbol files; it generates PDB and source files on demand and hands them to the debugger. That lets you step into a third-party assembly in Visual Studio, and a status window shows what was generated and what failed.
Explore .NET Libraries with Assembly Search and Navigation
dotPeek indexes your assemblies and the ones they reference, so search is fast across a whole dependency chain. Bookmarks, a metadata node, and a Process Explorer for decompiling running .NET modules round out the toolset.
JetBrains dotPeek Download and System Requirements
Getting dotPeek is simple, but a few details are worth knowing before you click download.
Is JetBrains dotPeek Free?
Yes. JetBrains states on its download page that dotPeek is free with no license key required. Other dotUltimate tools, such as ReSharper, are paid and offer trials.
Download dotPeek for Windows 10 and Windows 11
dotPeek is a Windows application that runs on current Windows 10 and Windows 11 systems. Check the official page for exact requirements, and keep an internet connection on, since the installer needs one.
Step by step:
- Open the official JetBrains dotPeek page.
- Click the download button.
- Run the installer when it finishes.
You can read more on the official JetBrains dotPeek page.
Download the Latest JetBrains Dotpeek Version
JetBrains uses yearly version numbers like 2025.3 and 2026.1, followed by smaller fixes. At the time of writing, the 2026.1 series was current and 2026.2 early access builds were appearing. Download from the official site for the newest stable build, or use the JetBrains Toolbox App for automatic updates.
dotPeek Installer and Portable Version Options
Older releases shipped an MSI plus 32-bit and 64-bit standalone files. Today the standard route is the installer or Toolbox App, so check the download page if you need a portable setup.
| Option | Best For | Needs Install? |
|---|---|---|
| Web installer | Most users | Yes |
| Toolbox App | Easy updates | Yes |
| Standalone executable (older builds) | Quick use on one PC | No |
Does JetBrains dotPeek Support macOS or Linux?
No. dotPeek is built for Windows, with no official macOS or Linux version. JetBrains Rider includes a built-in decompiler on every platform, and ILSpy has cross-platform builds.
How to Install and Set Up JetBrains dotPeek
Setup takes only a few minutes. Follow these steps in order.
How to Install dotPeek on Windows
- Download the installer from the official JetBrains site.
- Double-click the file and follow the prompts.
- Choose an install location, or keep the default.
- Finish the setup and launch the app.
Caution: If Windows shows a security prompt, confirm the publisher is JetBrains s.r.o. before continuing.
How to Launch dotPeek and Configure Its Settings
Open dotPeek from the Start menu. Go to Tools > Options to adjust the color scheme, decompiler preferences, and symbol server options. Keep the defaults at first and tune later.
How to Open DLL and EXE Files in dotPeek
You have three easy ways:
- Choose File > Open and pick your file.
- Drag and drop the file into the Assembly Explorer.
- Right-click a file in Windows Explorer if you have set up an association.
How to Add and Browse .NET Assemblies
Add as many assemblies as you like and jump between a library and its dependencies. Double-click a type to open its decompiled code, filter long lists with the search box, and use bookmarks to mark spots to revisit.
How to Configure dotPeek as a Default Assembly Viewer
Right-click a DLL, choose Open with, pick dotPeek, and tick the option to always use it. Some developers skip this, since double-clicking a DLL normally does nothing useful anyway.
How to Use JetBrains dotPeek to Decompile DLL Files
Now for the fun part. Here is how to turn a compiled file into readable code.
How to View C# Source Code from a DLL File
- Open dotPeek and load your DLL.
- Expand the assembly in the Assembly Explorer.
- Open a namespace and double-click a class.
Quick answer: To view C# from a DLL, open it in dotPeek, expand the assembly tree, and double-click a type. dotPeek shows the decompiled C# instantly.
How to Decompile a .NET EXE File
The process is the same as for a DLL. Load the EXE and start with the entry point, usually a class named Program with a Main method. Only managed EXE files work; a native Windows program will not open as code.
How to View IL Code in dotPeek
Open any type, then open the IL Viewer from the Windows menu. Use it next to the C# view to see how a line of C# becomes runtime instructions.
How to Search and Navigate Decompiled Code
- Go to Everything to jump to any type or symbol
- Find Usages to see where a member is used
- Go to String to search text inside the code
- Navigate To for base, derived, and related types
A good habit: start broad with search, then narrow down with usages.
How to Export Decompiled Code to a Visual Studio Project
- Right-click the assembly in the Assembly Explorer.
- Choose Export to Project.
- Pick a folder and confirm.
dotPeek writes a .csproj and the source files. Open it in Visual Studio and try a build. Missing references are the most common cause of errors.
Can dotPeek Recover the Original C# Source Code?
Not exactly. dotPeek recovers equivalent C# code, not the author’s original files. Comments are gone, local variable names may be lost without debug info, and structure can look different because the compiler rewrites loops and lambdas. Think of it as a faithful sketch, not a photocopy.
Is JetBrains dotPeek Safe to Use?
For most people, yes, as long as you get it from the right place. The bigger risk is usually the files you open, not the tool.
How to Download dotPeek from the Official Website
Always use the official JetBrains site or the Toolbox App. Avoid random “free download” sites, since bundled installers often spread unwanted software.
Safety checks: Confirm the URL belongs to jetbrains.com, check that the installer is signed by JetBrains, and never download a “cracked” version. dotPeek is already free.
Is dotPeek Safe for Opening DLL and EXE Files?
Opening a file in a decompiler is generally safer than running it, since dotPeek reads the file and does not execute it. Still, keep your antivirus on and analyze unknown samples inside a virtual machine.
Legal note: Decompiling software you do not own may break its license terms or local rules. Use dotPeek for your own code, open-source libraries, and cases where you have permission.
What Are the Limitations of .NET Decompilation?
- Comments and original formatting are lost.
- Obfuscated code is harder to read.
- Some compiler-generated code does not map cleanly back to C#.
- Native and non-.NET code cannot be decompiled.
JetBrains dotPeek Pros and Cons
No tool is perfect. Here is an honest look at both sides.
Advantages of Using dotPeek
- Free for everyone, with no license key.
- Strong navigation and search, inherited from ReSharper.
- Exports to Visual Studio projects.
- Can act as a symbol server and generate PDB files.
- Polished, familiar JetBrains interface.
- Regular updates from a trusted vendor.
Limitations to Consider Before Installing dotPeek
- Windows only, with no official Mac or Linux build.
- Not open source, unlike ILSpy.
- No built-in debugger; it supports debugging through the symbol server.
- Some reviewers find startup slow, especially inside Visual Studio.
- .NET assemblies only, so Mono or Xamarin builds may not work as hoped.
| Pros | Cons |
|---|---|
| Free to use | Windows only |
| Excellent search and navigation | Closed source |
| Project export and PDB generation | No standalone debugger |
| Trusted JetBrains support | .NET only |
JetBrains dotPeek vs. ILSpy and Other .NET Decompilers
Choosing a decompiler comes down to your platform, your budget, and what you want to do with the code.
dotPeek vs. ILSpy: Which .NET Decompiler Is Better?
ILSpy is a free, open-source decompiler from the ICSharpCode team, while dotPeek is free but closed source. dotPeek usually wins on navigation, search, and polish. ILSpy wins on openness, a lightweight feel, and cross-platform options.
dotPeek vs. dnSpy: Features and Use Cases
dnSpy can debug and edit assemblies directly, which dotPeek does not offer. The original project was archived, and the community continues it as dnSpyEx. Choose it to debug a program with no source; choose dotPeek when you only need to read and understand code.
dotPeek vs. Visual Studio Assembly Browsing
Visual Studio shows metadata for a referenced DLL, and newer versions can decompile on the fly, which suits quick lookups. dotPeek goes deeper with a full assembly list, advanced search, PDB generation, and project export.
Which C# Decompiler Is Best for .NET Developers?
| Need | Best Pick |
|---|---|
| Free, polished, Windows | dotPeek |
| Open source or cross-platform | ILSpy |
| Debugging compiled code | dnSpyEx |
| Already using JetBrains IDEs | Rider (built-in decompiler) |
| Quick peek inside Visual Studio | Built-in decompilation |
Many developers keep two tools installed, so if one struggles with a tricky assembly, the other might cope better.
Best JetBrains dotPeek Alternatives
If dotPeek does not fit your setup, these tools are worth a look.
ILSpy: Open-Source .NET Assembly Decompiler
ILSpy is the most popular free alternative. It is open source, fast, and actively maintained, with a command-line version, Visual Studio extensions, and builds for other platforms.
dnSpy and dnSpyEx: .NET Assembly Inspection and Debugging
dnSpyEx is a community-maintained continuation of dnSpy. Its strength is debugging and editing compiled assemblies. Use it responsibly and only on software you are allowed to analyze.
Other Tools for Viewing and Decompiling DLL Files
- JetBrains Rider: a full .NET IDE with a built-in decompiler on Windows, macOS, and Linux.
- ReSharper: adds decompiling inside Visual Studio.
- Telerik JustDecompile: a free decompiler from a commercial vendor.
- Visual Studio: handy for quick looks at referenced assemblies.
If you like JetBrains tools in general, you may also enjoy our guide to JetBrains RubyMine, another IDE from the same family.
Common JetBrains dotPeek Problems and Fixes
Most issues are easy to solve. Here are the ones people hit most often.
dotPeek Cannot Open a DLL or EXE File
Likely cause: The file is not a managed .NET assembly. Fix: Confirm it was built with .NET, since native C or C++ files cannot be opened. Also check that the file is not corrupted or blocked by Windows in its properties.
Decompiled C# Code Looks Different from the Original
Likely cause: This is normal, because compilers change code and remove comments. Fix: Compare with the IL view, and for obfuscated code try a deobfuscation tool first.
dotPeek Cannot Find Types or Dependencies
Likely cause: Referenced assemblies are missing from your list. Fix: Add the dependent DLLs to the Assembly Explorer, or place them in the same folder.
How to Fix Common Installation and Compatibility Issues
- Re-download the installer from the official site.
- Run it as administrator.
- Use the 64-bit build on 64-bit Windows, especially for symbol server work.
- Update Windows and .NET components.
- Check the Project/PDB Generation Status window if PDB creation fails.
If nothing works, try the Toolbox App, which handles updates cleanly and often avoids install errors.
Frequently Asked Questions About JetBrains dotPeek
Yes. JetBrains offers dotPeek for free with no license key required.
It depends on your needs. dotPeek is great for Windows users, ILSpy for open source, and dnSpyEx for debugging.
Yes. It makes it easy to inspect libraries, follow code, and debug third-party assemblies.
No. It only works with managed .NET assemblies, not native C or C++ DLLs.
Yes, it can export a DLL as a Visual Studio project. The code is equivalent, not identical, to the original.
No, dotPeek is Windows only. Rider and ILSpy are good options on Mac and Linux.
dotPeek is closed source with strong navigation, while ILSpy is open source and cross-platform.
Final Verdict: Is JetBrains dotPeek Worth Using?
If you work with .NET on Windows, dotPeek is absolutely worth a download. It is free, polished, and packed with navigation tools that save real time when you explore unfamiliar code. It turns a locked DLL into something you can read, search, and learn from.
It is not perfect, and no decompiler is. You will not get your original comments back, and Mac or Linux users will need another tool. Still, for understanding libraries and recovering lost work, dotPeek earns its place on your machine, and I think you will be glad you installed it.
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