An Introduction to .NET Core

For over a decade, the .NET Framework has been the go-to platform for building Windows applications. But the software world has changed, and the need for applications that can run anywhere—on Windows, macOS, and Linux, in the cloud and in containers—has become paramount. To meet this need, Microsoft has created .NET Core.

.NET Core is not just a new version of the .NET Framework; it's a complete, open-source redesign, built from the ground up to be a modern, modular, and high-performance platform for the new era of software development.

What is .NET Core?

.NET Core is an open-source, general-purpose development platform maintained by Microsoft and the .NET community on GitHub. It is cross-platform, supporting Windows, macOS, and Linux, and can be used to build device, cloud, and IoT applications.

Key Design Principles of .NET Core

1. Cross-Platform

This is the most significant feature. You can write your .NET Core application on a Mac, collaborate with a developer on Windows, and deploy it to a Linux server in the cloud. This flexibility is essential for modern development teams.

2. Open-Source

The entire .NET Core platform, from the runtime to the base class libraries, is open-source under a permissive license. This fosters transparency, allows the community to contribute, and builds trust in the platform's future.

3. High Performance

Performance is a top priority for .NET Core. The team has made huge investments in optimizing the runtime and libraries, making .NET Core one of the fastest web frameworks available today.

4. Modular and Command-Line Centric

.NET Core is designed to be modular. Applications can be deployed with only the dependencies they need. The platform is built around a powerful command-line interface (CLI), the dotnet command, which can be used to create, build, test, and publish applications. This makes it easy to integrate .NET Core into any automated build and deployment pipeline.

5. Side-by-Side Installation

Different versions of .NET Core can be installed on the same machine without interfering with each other. This allows different applications on the same server to target different versions of .NET Core, which makes upgrading much safer and easier.

What Can You Build with .NET Core?

As of early 2018, with .NET Core 2.0, you can build:

• Web Applications and APIs: Using ASP.NET Core, you can build powerful, high-performance web apps and RESTful services.
• Console Applications: For building command-line tools and background services.
• Libraries: Reusable libraries that can be shared across different project types.

Support for desktop and mobile applications is planned for future versions, but for now, the focus is squarely on web and cloud development.

The .NET Standard

To help manage the different .NET platforms (.NET Framework, .NET Core, and Xamarin), Microsoft introduced the .NET Standard. The .NET Standard is a formal specification of .NET APIs that are available on all .NET implementations. When you build a library that targets a specific .NET Standard version, you can be sure that it will work on any platform that implements that version of the standard. This is the key to writing portable, reusable code in the .NET ecosystem.

The Future is .NET Core

While the .NET Framework is still supported, all future innovation is happening in .NET Core. Its cross-platform nature, open-source model, and focus on performance make it the clear path forward for all .NET development.

If you are a .NET developer, now is the time to start learning .NET Core. It's a powerful and flexible platform that will enable you to build the next generation of modern applications.