SYSTEM ONLINE // C# .NET

CODE THAT
DOES STUFF.

C# isn't just a language. It's the engine behind games, apps, servers, tools, AI systems and entire virtual worlds. New to programming entirely? Good — every tutorial here starts from zero.

Program.cs — C#
// Make something happen.
using System;

class Program
{
    static void Main()
    {
        Console.WriteLine("Hello, future.");
        Console.WriteLine("C# can build almost anything.");
    }
}

One language. Ridiculous range.

From your first console app to multiplayer VR, C# scales with you. Here are a few places where it shines.

🎮

Game Development

Power gameplay systems, physics, UI, multiplayer and VR experiences with engines like Unity.

UNITY + C#
🌐

Web & APIs

Build fast backends, REST APIs, real-time services and full web applications with .NET.

ASP.NET CORE

Automation

Write tools that manipulate files, process data, launch programs and automate repetitive work.

SYSTEM.IO
🧠

AI & Data

Connect models and services, process huge datasets and build intelligent application features.

ML.NET + .NET
📱

Apps

Create cross-platform applications for desktop and mobile while sharing code between platforms.

.NET MAUI
🛠️

Developer Tools

Build your own editors, launchers, patchers, command-line tools and workflows.

DOTNET CLI

How C# grew up.

A quick look at the ecosystem that turned C# into a general-purpose powerhouse.

2000C# announced
.NETRuntime ecosystem
UnityGame dev powerhouse
Things you can build
01 — THE START

C# was introduced by Microsoft as a modern, strongly typed language designed for the .NET platform.

02 — OPEN SOURCE

The .NET ecosystem expanded across operating systems and became open source, making C# much more cross-platform.

03 — GAME ON

Unity helped make C# a familiar tool for thousands of game developers, from tiny prototypes to huge projects.

04 — YOUR TURN

Build a game. Make an app. Automate something. Create a server. The language is only the beginning.

Make something weird.

The best way to learn C# is to give it a job to do. Ten tutorials are waiting, from your first variable to a multiplayer game.

Browse tutorials →

Learn it. Build it. Break it. Fix it.

Every tutorial opens as its own lesson with diagrams, real code, and a choice: read the full script, or build it piece-by-piece yourself.

🔍

Break some code.

A live, simplified C# console right in your browser. Pick an example below, or write your own — then hit RUN.

Program.cs
CONSOLE OUTPUT
Ready. Press RUN to execute your code.

🎯 Warm-up challenge

Make the console print the numbers 1 through 5, one per line.