Target frameworks

NuGet uses target framework references in a variety of places to specifically identify and isolate framework-dependent components of a package:

• project file: For SDK-style projects, the .csproj contains the target framework references.
• .nuspec manifest: A package can indicate distinct packages to be included in a project depending on the project's target framework.
• .nupkg folder name: The folders inside a package's lib folder can be named according to the target framework, each of which contains the DLLs and other content appropriate to that framework.
• packages.config: The targetframework attribute of a dependency specifies the variant of a package to install.

Supported frameworks

A framework is typically referenced by a short target framework moniker or TFM. In .NET Standard this is also generalized to TxM to allow a single reference to multiple frameworks.

The NuGet clients support the frameworks in the table below. Equivalents are shown within brackets []. Note that some tools, such as dotnet, might use variations of canonical TFMs in some files. For example, dotnet pack uses .NETCoreApp2.0 in a .nuspec file rather than netcoreapp2.0. The various NuGet client tools handle these variations properly, but you should always use canonical TFMs when editing files directly.

Deprecated frameworks

The following frameworks are deprecated. Packages targeting these frameworks should migrate to the indicated replacements.

Precedence

A number of frameworks are related to and compatible with one another, but not necessarily equivalent:

NET Standard

.NET Standard simplifies references between binary-compatible frameworks, allowing a single target framework to reference a combination of others. (For background, see the .NET Primer.)

The NuGet Get Nearest Framework Tool simulates what NuGet uses to select one framework from many available framework assets in a package based on the project's framework.

The dotnet series of monikers should be used in NuGet 3.3 and earlier; the netstandard moniker syntax should be used in v3.4 and later.

Portable Class Libraries

To define a target framework that refers to multiple child-target-frameworks, the portable keyword use used to prefix the list of referenced frameworks. Avoid artificially including extra frameworks that are not directly compiled against because it can lead to unintended side-effects in those frameworks.

Additional frameworks defined by third parties provide compatibility with other environments that are accessible in this manner. Additionally, there are shorthand profile numbers that are available to reference these combinations of related frameworks as Profile#, but this is not a recommended practice to use these numbers as it reduces the readability of the folders and .nuspec.

Additionally, NuGet packages targeting Xamarin can use additional Xamarin-defined frameworks. See Creating NuGet packages for Xamarin.