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Modern VSIX Project Template

The C# Modern VSIX Project template guides you through creating a VSSDK, VisualStudio.Extensibility, or hybrid extension in Visual Studio. You can use Microsoft.VisualStudio.Sdk.Build as the top-level project SDK (the default) or Microsoft.NET.Sdk with explicit package references. If you already have a VSIX project, migrate the existing project to keep its extension ID and assets.

Use this guide for new projects in Visual Studio 18.11 or later. The template handles VSIX packaging, so you don't also need to follow the older VSIX project workflow. That workflow is for earlier development environments or maintaining existing projects; the modern template can still create projects that target Visual Studio 2022 (17.14).

Prerequisites

  • Visual Studio 18.11 or later with the Visual Studio SDK installed ↗. The Modern VSIX Project template and project SDK are available starting in 18.11; the wizard can also create projects targeting Visual Studio 2022 (17.14).

Create the project in Visual Studio

  1. Select File > New > Project, search for Modern VSIX Project, select the template, then select Next.
  2. Enter a project name and location, then select Next.
  3. Under Target VS Version, choose Visual Studio 2026 (18.11) (the default) or Visual Studio 2022 (17.14).
  4. Under Extension Type, select VisualStudio.Extensibility (Out-Of-Process) for new features supported by VisualStudio.Extensibility. The default is Visual Studio SDK (VSSDK, In-Process); select Hybrid (VSSDK + VisualStudio.Extensibility, In-Process) only when you need both models.
  5. Keep Use top-level Visual Studio SDK selected to use Microsoft.VisualStudio.Sdk.Build, or clear it to use Microsoft.NET.Sdk with explicit package references. Set Publisher and select Create.

Select Extension library only if the project is a shared library rather than a standalone VSIX.

Understand the generated project

For example, selecting VisualStudio.Extensibility (Out-Of-Process) and Visual Studio 2026 (18.11) with the top-level SDK produces a project like this:

<Project Sdk="Microsoft.VisualStudio.Sdk.Build">
  <PropertyGroup>
    <TargetFrameworks>vs18_11</TargetFrameworks>
    <ExtensionType>VisualStudio.Extensibility</ExtensionType>
    <LangVersion>latest</LangVersion>
  </PropertyGroup>
</Project>

With Use top-level Visual Studio SDK cleared and the same options selected, the project uses Sdk="Microsoft.NET.Sdk" and TargetFramework=net10.0-windows8.0, with explicit VSSDK build tools and VisualStudio.Extensibility package references.

Note

The Microsoft.NET.Sdk variant references Microsoft.VSSDK.BuildTools and sets VSSDKBuildToolsAutoSetup to true. The package defaults this setting to false; setting it to true imports the VSSDK build targets and supplies VSIX packaging and debugger defaults for standalone extensions. .pkgdef generation remains off by default (GeneratePkgDefFile=false); set it to true if your VSSDK package needs registration. DeployExtension is deprecated. It controls legacy deployment during a build and defaults to false; Visual Studio uses VsixDeployOnDebug (which defaults to true) when deploying the VSIX for debugging. The top-level project SDK imports the build targets itself and doesn't need VSSDKBuildToolsAutoSetup.

To inspect the selected SDK and target framework in Visual Studio, right-click the project in Solution Explorer and select Edit Project File. For VSSDK and hybrid projects, the template also creates source.extension.vsixmanifest; the out-of-process option doesn't create a manifest.

The top-level SDK maps vs17_14 and vs18_11 to .NET Framework 4.8 for in-process and hybrid extensions. Out-of-process extensions use .NET 8 or .NET 10 for Windows, respectively.

Specify the project SDK version

The top-level SDK option creates a project without a pinned SDK version, as shown in the example. If you need a fixed Microsoft.VisualStudio.Sdk.Build ↗ version across build environments, specify it in global.json or the project's Sdk attribute. See How MSBuild resolves project SDKs ↗ for details.

Build and test the VSIX in Visual Studio

  1. For VSSDK and hybrid projects, open source.extension.vsixmanifest and set the extension ID, publisher, supported installation targets, and prerequisites. For out-of-process projects, follow the VisualStudio.Extensibility getting started guide to configure extension metadata instead.
  2. Select Build > Build Solution to build the VSIX.

Inspect the built VSIX and test it in the targeted Visual Studio version before publishing. To update an existing VSSDK or hybrid extension rather than create a separate one, keep its manifest ID and increment its version.

See also

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