.NET Core vs ASP.NET Core

Update 2020: Do note that ASP.NET Core 3 and higher now depend on .NET Core and can no longer be used on .NET Framework. The below description is for ASP.NET Core 1.x-2.x; the layer separation still holds true for ASP.NET Core 3.0 but the ASP.NET Core layer can no longer be used on top of .NET Framework in 3.0+.

.NET Core is a runtime. It can execute applications that are built for it.

ASP.NET Core is a collection of libraries that form a Framework for building web applications. ASP.NET Core libraries can be used on both .NET Core and the "Full .NET Framework" (which has shipped with windows for many years).

The confusing part is that an application using the libraries and tools of ASP.NET Core is usually referred to as "ASP.NET Core Application", which in theory doesn't say if it is built for .NET Core or .NET Framework. So an "ASP.NET Core Application" is also a ".NET Core Application" or a ".NET Framework Application".

https://i.stack.imgur.com/3amI1.png

Here you can see that ASP.NET Core is built "on top of" both .NET Framework and .NET Core, while "ASP.NET" (now often referred to as "classic ASP.NET") is .NET Framework only.

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ASP.NET Core using .NET Core - all dependencies are self-contained, can use most NuGet packages, can't use Windows-specific packages, can execute on Windows, Linux, and Mac.

ASP.NET Core using .NET Framework - most dependencies are self-contained, only executes on Windows, will have access to Windows-specific NuGet packages, needs the .NET framework version which is targeted installed on the machine.

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ASP.NET Core is one of the workloads supported by .NET Core.

From .NET Core guide:

By itself, .NET Core includes a single application model -- console apps -- which is useful for tools, local services and text-based games. Additional application models have been built on top of .NET Core to extend its functionality, such as: ASP.NET Core Windows 10 Universal Windows Platform (UWP) Xamarin.Forms

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The .NET Framework is on its last release. There will not be another one after 4.8. Microsoft will continue with .NET Core. From this time you should prefer .NET Core on your projects.

Update (Official):

.NET 5 is the next major release of .NET Core following 3.1. We named this new release .NET 5 instead of .NET Core 4 for two reasons:

We skipped version numbers 4.x to avoid confusion with .NET Framework 4.x. We dropped "Core" from the name to emphasize that this is the main implementation of .NET going forward. .NET 5 supports more types of apps and more platforms than .NET Core or .NET Framework. ASP.NET Core 5.0 is based on .NET 5 but retains the name "Core" to avoid confusing it with ASP.NET MVC 5. Likewise, Entity Framework Core 5.0 retains the name "Core" to avoid confusing it with Entity Framework 5 and 6.

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.NET Core is the next evolution of the .NET Framework, that allows Microsoft technology to be hosted on other OS platforms, rather than Windows.

ASP.NET is the web framework provided by Microsoft for building:

server-side rendered web pages/websites

server-side components for SPAs

MVC-fashion apps

web services/web APIs/microservices

ASP.NET runs only on Windows platforms.

Since .NET Core was created to provide the capability of running Microsoft tech on top of Linux/macOS, it implies that ASP.NET Core is the evolution of ASP.NET in the direction of multi-platform support.

In conclusion:

ASP.NET Core runs on both .NET Core and .NET 5.0, on top of multiple OS platforms: Windows, Linux & macOS.

ASP.NET 4.x (ASP.NET/ASP.NET MVC) runs on the .NET Framework only, on top of Windows OS.

https://i.stack.imgur.com/9ccUx.png

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I would like to add that there is something called middleware injection in .NET Core request pipeline. If implemented correctly this is very useful, as it can intercept application exceptions automatically and makes logging much easier (in one place instead of logging in every method).

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