C# Dev Kit 11.0 is available in pre-release as part of the .NET 11 cycle, but Microsoft had not yet released it to the stable channel as of October 7, 2026. The update aligns the extension’s version number with .NET and reworks its architecture, with Microsoft reporting substantially faster builds on one large solution. Those performance figures are vendor measurements, not a guarantee for every project.
What is C# Dev Kit 11?
C# Dev Kit is Microsoft’s extension for developing C# and .NET applications in Visual Studio Code. Version 11.0 replaces the previous 3.3 version number, aligning the extension with the .NET 11 release cycle. Microsoft describes the release as a rearchitecture intended to make the tools faster and lighter, rather than simply a version-number change.
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Microsoft announced the update on October 6, 2026. On October 7, it said C# Dev Kit 11.0 was available in pre-release and was still being prepared for stable release. Drew Noakes, a principal software engineer at Microsoft, framed the goal this way: “We developers know just how fast computers can be, and we want to feel that speed in our tools.” Microsoft’s announcement is an overview; the company said it would cover the architecture, Native AOT server, cached project loading, and build improvements in later posts.
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What’s new in C# Dev Kit 11?
Faster incremental builds
Microsoft attributes the build improvements to fast up-to-date checks and Build Acceleration for incremental builds. The company published results from its 407-project Aspire solution, comparing C# Dev Kit 3.3 with version 11.0:
#1 Best Overall
| Build scenario | C# Dev Kit 3.3 | C# Dev Kit 11.0 | Microsoft’s reported result |
|---|---|---|---|
| No changes to build | 34.4 seconds | 0.88 seconds | 39× faster |
| One C# file changed | 36.1 seconds | 2.1 seconds | 17× faster |
These are Microsoft’s measurements on that named solution, not independent benchmark results. Build times depend on the project and workload, so the figures should not be read as a promised speed-up for every C# workspace. For a meaningful comparison, match both the workload and change type: an unchanged build is not the same test as a build after editing one file. Microsoft’s performance report provides the measurements.
Lower memory use in the Dev Kit server
Microsoft says version 11 uses a more compact in-memory representation of projects and Native AOT to reduce memory use. The scope of its comparison is the C# Dev Kit server process or processes. Roslyn runs separately, and Visual Studio Code has its own memory footprint; Microsoft says those are largely unchanged. The reported server-memory improvement therefore should not be treated as a reduction in total memory used by VS Code and all related processes.
How does C# Dev Kit 11 relate to .NET 11?
The extension’s pre-release status and the .NET SDK’s release status are separate. Microsoft announced .NET 11 Release Candidate 1 on September 8, 2026, and says that RC has a go-live support license. That does not make C# Dev Kit 11.0 a stable release: Microsoft still described the extension as pre-release on October 7. See Microsoft’s .NET 11 RC1 announcement for the SDK’s status.
The official .NET download page lists SDK 11.0.100-rc.1, with C# 14.0, F# 10.0, and Visual Basic 17.13. SDK downloads are listed for Linux, macOS, and Windows. Check the .NET 11 download page for the available packages for your operating system.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.How do I try C# Dev Kit 11 with .NET 11?
- Install the .NET 11 RC1 SDK. Use the download for Linux, macOS, or Windows from the .NET 11 download page. A local .NET SDK is required for .NET projects in VS Code.
- Install the pre-release C# Dev Kit. In Visual Studio Code, find C# Dev Kit in the Extensions view and select its pre-release version or pre-release channel. Microsoft identified 11.0 as pre-release; do not assume the stable extension channel has the same version.
- Open a .NET project and check that VS Code detects the SDK. C# Dev Kit adds solution management, project templates, and test discovery and debugging. The C# extension supplies core language services. IntelliCode for C# Dev Kit is optional and adds an AI-assisted development experience.
The exact extension-channel controls can change between VS Code releases. Microsoft’s Visual Studio Code guide to using .NET explains the extension setup and SDK prerequisite.
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