What is .NET Core?

.NET Core is a cross-platform, open-source framework developed by Microsoft for building modern applications like web apps, APIs, microservices, cloud apps, and even desktop software.

Simple Explanation

Think of .NET Core as a toolkit + runtime that lets you write code (usually in C#) and run it on:

• Windows
• Linux
• macOS

Earlier, the old .NET Framework was mostly limited to Windows. .NET Core removed that limitation.

Key Features

1. Cross-Platform

• Write once, run anywhere (Windows, Linux, macOS).

2. High Performance

• Faster than the older .NET Framework, optimized for modern apps and cloud.

3. Open Source

• Source code is publicly available and maintained on GitHub.

4. Built for Cloud & Microservices

• Works well with containers like Docker and cloud platforms like Azure.

5. Built-in Dependency Injection

• DI is integrated by default (unlike older .NET Framework).

Main Components

• CLR (Common Language Runtime) → Executes your code
• Base Class Libraries → Pre-built functions (collections, IO, etc.)
• ASP.NET Core → For building web apps & APIs
• Entity Framework Core → ORM for database access

.NET Core vs .NET Framework

Example Use

You can build:

• Web APIs (REST services)
• MVC web applications
• Real-time apps (SignalR)
• Microservices
• Background jobs

Note (Important)

Today, .NET Core has evolved into just “.NET” (starting from .NET 5 and later).

So:

• .NET Core 3.1 → Old naming
• .NET 6, 7, 8 → Modern unified platform

In One Line

.NET Core is a fast, modern, cross-platform framework for building scalable applications using C#.