What is .NET Core?

Beginner Updated January 20, 2025

🚀 Complete Tutorial on .NET Core: Cross-Platform Development for Modern Applications

.NET Core has revolutionized the software development landscape with its lightweight, cross-platform capabilities and modular design. Whether you're a seasoned developer or new to the .NET ecosystem, this comprehensive guide will walk you through everything you need to know about .NET Core — from its architecture and setup to building, deploying, and scaling real-world applications.

🧠 What is .NET Core?

.NET Core is a free, open-source, cross-platform framework developed by Microsoft for building modern, cloud-based, and internet-connected applications.

Unlike the traditional .NET Framework which is Windows-only, .NET Core runs on:

  • 🪟 Windows
  • 🐧 Linux
  • 🍏 macOS

.NET Core is now part of the unified .NET 5+ platform, simply called .NET, starting from version 5. However, understanding .NET Core is critical because it's the foundation of this modern runtime.

🌟 Why Use .NET Core?

Here's why .NET Core is a favorite among developers building enterprise and cloud-native solutions:

| Feature                      | Benefit                                                                 |
|-----------------------------|-------------------------------------------------------------------------|
| Cross-Platform              | Develop once, run on Windows, Linux, or macOS                           |
| Open Source                 | Transparent development with community contributions                    |
| High Performance            | Benchmark-leading speed for web APIs and microservices                  |
| Modular and Lightweight     | Use only the libraries you need                                         |
| Unified Tooling             | CLI tools, Visual Studio, and VS Code support                           |
| Microservice Friendly       | Ideal for Docker containers and scalable services                       |
| Side-by-side Installation   | Install multiple runtime versions on the same machine                   |

🛠 Installing .NET Core

🔹 Step 1: Download the SDK

Visit the official .NET download page and select the latest version for your operating system.

🔹 Step 2: Verify Installation

Open your terminal or command prompt:

dotnet --version

If installed correctly, this command will output the version number.

🏗️ Understanding .NET Core Architecture

The architecture of .NET Core is built around modularity, portability, and high performance.

                 .-------------------------------.
                 |      Your Application         |
                 '-------------------------------'
                             |
        .-----------------------------------------------.
        |      Base Class Libraries (System.*, etc.)     |
        '-----------------------------------------------'
                             |
     .------------------------------------------.
     |         .NET Runtime (CoreCLR)           |
     '------------------------------------------'
                 |               |
          JIT Compiler       Garbage Collector

Key Components:

  • CoreCLR – The runtime that handles memory management, JIT compilation, and threading.
  • CoreFX – The foundational libraries (collections, file I/O, networking).
  • Roslyn – The .NET compiler platform for C# and VB.NET.