Mono 6.8.0

Online C# Compiler & Editor

Name: myCompiler C#
Author: myCompiler

myCompiler is a free online C# compiler, editor and code runner that lets you write, run, and share C# code directly in your browser. It works as your C# playground, sandbox, fiddle, cloud compiler, and online REPL. No downloads, no installation needed. Just open the editor and start coding with syntax highlighting, autocomplete, and instant output.

Start coding in C# How it works

27+ languages Used by 1M+ developers Free forever

main.cs

using System;
using System.Linq;

class Program {
    static void Main() {
        int[] numbers = {1, 2, 3, 4, 5,
            6, 7, 8, 9, 10};
        var evens = numbers.Where(n => n % 2 == 0);
        var result = string.Join(", ", evens);
        Console.WriteLine($"Evens: {result}");
        Console.WriteLine($"Sum: {numbers.Sum()}");
    }
}

Output

Evens: 2, 4, 6, 8, 10 Sum: 55

How to run C# code online

Three steps to go from idea to running C# code in this online playground. No account required.

Write your code

Open the C# editor and start writing. The smart editor gives you syntax highlighting, autocomplete, and error detection as you type.

Click Run

Hit the Run button or press +Enter to run your C# code on secure, sandboxed cloud servers.

See results

Output appears instantly in the integrated terminal. Errors and exceptions show up with clear, helpful messages.

Everything you need to code in C#

A complete online C# IDE and coding playground in your browser. Write, run, and share code without any setup.

Zero setup required

Start coding in seconds with this browser-based C# interpreter. No downloads, no installations, no environment configuration. Open your browser, go to myCompiler, and start writing C# code immediately.

Works on any device with a web browser. Desktop, laptop, tablet, phone, Chromebook. There is nothing to install and nothing to configure.

Feature-rich code editor

Write C# with a professional-grade code editor built into your browser. Syntax highlighting colors your code for readability, making keywords, strings, and functions easy to distinguish at a glance.

Intelligent autocomplete suggests methods and properties as you type, and real-time error detection catches mistakes before you run your code.

Multi-file projects

Create and manage multiple files in a single project. Use the file sidebar to organize your code into modules, then import them across files just like in a desktop IDE.

Build modular applications with proper project structure. Each file is editable, and you can switch between them instantly.

Run code instantly

Click the Run button or press +Enter to execute your C# code instantly. This online code runner displays output immediately in the integrated terminal panel. Your code runs on secure, sandboxed cloud servers and results appear in seconds.

Error messages and tracebacks are displayed clearly, making it easy to find and fix issues. The terminal supports ANSI colors for rich output formatting.

Ready to try it? Write and run your first C# program in seconds.

Open C# editor

C# on myCompiler

myCompiler runs Mono 6.8.0, always up to date with the latest stable release. You get a full browser-based IDE with syntax highlighting, intelligent code completion, multi-file project support, a built-in terminal for real-time output, and standard input (stdin) for interactive programs. Write, compile, run, and debug C# code on any device. Desktop, laptop, tablet, phone, Chromebook. Zero downloads, zero configuration, and no sign-up required. Save your programs with a unique URL and share them with anyone. You can also embed a working C# editor on your own website.

Use this online C# playground as a quick code executor for testing snippets, a coding sandbox for learning, or a cloud compiler for coding interview preparation. The editor includes dark mode for comfortable coding, keyboard shortcuts for faster workflows, and clear error messages with line numbers so you can debug quickly. Students use it for homework and practice. Teachers use it to share working examples. Developers use it to prototype ideas. myCompiler is beginner-friendly, fast, and completely free. It works in any modern web browser.

Start coding in C#

C# code examples

Common C# patterns you can try in the online compiler. Each example is ready to run.

Hello World in C#

main.cs

using System;

class Program {
    static void Main() {
        Console.WriteLine("Hello, World!");
    }
}

Variables and Data Types in C#

main.cs

using System;

class Program {
    static void Main() {
        string name = "Alice";
        int age = 30;
        double height = 5.6;
        bool isStudent = true;
        Console.WriteLine($"{name} is {age} years old");
    }
}

If-Else Conditionals in C#

main.cs

using System;

class Program {
    static void Main() {
        int x = 10;
        if (x > 0) Console.WriteLine("Positive");
        else if (x == 0) Console.WriteLine("Zero");
        else Console.WriteLine("Negative");
    }
}

For and While Loops in C#

main.cs

using System;

class Program {
    static void Main() {
        for (int i = 0; i < 5; i++)
            Console.WriteLine($"Count: {i}");

        string[] fruits = {"apple", "banana", "cherry"};
        foreach (string fruit in fruits)
            Console.WriteLine(fruit);
    }
}

Functions in C#

main.cs

using System;

class Program {
    static string Greet(string name, string greeting = "Hello") {
        return $"{greeting}, {name}!";
    }
    static void Main() {
        Console.WriteLine(Greet("Alice"));
        Console.WriteLine(Greet("Bob", "Hi"));
    }
}

Arrays and Collections in C#

main.cs

using System;
using System.Collections.Generic;

class Program {
    static void Main() {
        var fruits = new List<string> { "apple", "banana", "cherry" };
        fruits.Add("date");
        Console.WriteLine(fruits[1]);

        var person = new Dictionary<string, object> { {"name", "Alice"}, {"age", 30} };
        Console.WriteLine(person["name"]);
    }
}

Classes and Objects in C#

main.cs

using System;

class Dog {
    public string Name { get; }
    public string Breed { get; }
    public Dog(string name, string breed) { Name = name; Breed = breed; }
    public string Bark() => $"{Name} says Woof!";
}

class Program {
    static void Main() {
        var dog = new Dog("Rex", "Labrador");
        Console.WriteLine(dog.Bark());
    }
}

Error Handling in C#

main.cs

using System;

class Program {
    static void Main() {
        try {
            int result = int.Parse("not a number");
        } catch (FormatException e) {
            Console.WriteLine($"Error: {e.Message}");
        } finally {
            Console.WriteLine("Done");
        }
    }
}

File I/O in C#

main.cs

using System;
using System.IO;

class Program {
    static void Main() {
        File.WriteAllText("output.txt", "Hello, File!");
        string content = File.ReadAllText("output.txt");
        Console.WriteLine(content);
    }
}

LINQ Queries in C#

main.cs

using System;
using System.Linq;
using System.Collections.Generic;

class Program {
    static void Main() {
        var numbers = new List<int> { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
        var evens = numbers.Where(n => n % 2 == 0).ToList();
        var sum = numbers.Sum();
        Console.WriteLine($"Evens: {string.Join(", ", evens)}");
        Console.WriteLine($"Sum: {sum}");
    }
}

Try these examples in the editor

How to take input in C# online

myCompiler supports standard input (stdin) for C# programs. Use C#'s standard input functions to read user input. Enter your input data in the stdin panel before running your program.

This works for both single-line and multi-line input. You can read strings and convert to numbers using the language's built-in I/O functions.

Try it yourself

main.cs stdin supported

using System;

class Program {
    static void Main() {
        string name = Console.ReadLine();
        int age = int.Parse(Console.ReadLine());

        Console.WriteLine($"Hello {name}!");
        Console.WriteLine($"You'll be {age + 1} next year.");
    }
}

stdin

Alice
25

Output

Hello Alice!
You'll be 26 next year.

No setup, no sign-up. Start writing C# code right now.

Start coding now

Getting started with C# online

You can start writing and running C# code right now without installing anything. Type your code, and click Run. This free C# code runner executes your program instantly and displays the output in the terminal panel below the editor. Open the C# online editor, type your code, and click Run.

If you're new to C#, use this online C# playground to start with the basics like variables, data types, conditionals, and loops. The code examples above cover all the fundamentals you need to get started. Each example can be copied into the sandbox and run immediately. No setup, no configuration.

As you progress, try creating multi-file projects, using libraries, and sharing your programs with others via URL. Sign up for a free account to save your work and build a personal library of programs. myCompiler works as a full online C# IDE right in your browser.

Who uses myCompiler

Whether you're learning to code, preparing for interviews, or prototyping ideas, myCompiler is built for you.

Students & Learners

Practice exercises, complete homework assignments, and experiment with code without installing anything on school or personal computers.

Teachers & Educators

Share code examples with students via unique URLs. Embed the compiler in course materials so students can run examples directly in the browser.

Interview Candidates

Practice coding interview problems, test algorithms, and verify solutions quickly during preparation for technical interviews.

Professional Developers

Quickly prototype ideas, test code snippets, or try out a library without setting up a local environment. Great for quick experiments.

Content Creators & Bloggers

Embed interactive examples in blog posts, tutorials, and documentation so readers can run code without leaving the page.

Teams & Collaborators

Share code snippets with colleagues via URLs. Others can view, run, and fork your code to build on your work.

myCompiler vs. local IDE

Why use an online C# compiler instead of installing one locally?

Feature	myCompiler	Local IDE
Setup time	Instant	Minutes to hours
Installation	None required	C# + IDE required
Device support	Any browser	Desktop only
Sharing code	One-click URL	Manual (file, git, etc.)
Languages	27+ in one place	One at a time
Cost	Free forever	Free to $$$
Works on Chromebook	Yes	Limited

What is C#?

C# (C-Sharp) is a modern, object-oriented programming language developed by Microsoft as part of the .NET platform. Designed by Anders Hejlsberg and released in 2000, C# was created to combine the raw power of C++ with the simplicity and safety of Visual Basic. It has evolved into one of the most feature-rich languages available, with each version bringing significant improvements.

C# runs on .NET, a cross-platform runtime that supports Windows, macOS, and Linux. Modern C# (versions 9–12) features records, pattern matching, nullable reference types, top-level programs, and primary constructors, making it concise and expressive while maintaining strong typing. Unity, the world's most popular game engine, uses C# as its primary scripting language.

What is C# used for?

C# is used for Windows desktop applications with WPF and WinForms, web applications and APIs with ASP.NET Core and Blazor, game development with Unity (mobile, console, VR/AR), cross-platform mobile apps with .NET MAUI, enterprise backend services, and cloud applications on Azure. Microsoft's extensive tooling ecosystem (Visual Studio, Azure DevOps) makes it a natural fit for enterprise software development.

C# for beginners

C# is an excellent language for beginners who want to learn object-oriented programming in a structured way. Its syntax is clear and consistent, the .NET runtime provides strong error messages, and Visual Studio (free Community edition) offers world-class tooling. Many game developers start with C# through Unity, which provides immediate visual feedback. Use myCompiler's online C# compiler to learn C# fundamentals, classes, interfaces, LINQ, and async/await, without installing .NET locally.

C# vs other languages

Compared to Java, C# has more modern language features (records, pattern matching, nullable references) and better Windows integration, while Java has broader cross-platform enterprise adoption and the Android ecosystem. Compared to Python, C# is faster, strictly typed, and better for large-scale applications, while Python is more concise for scripting and data science. Compared to F#, C# is more imperative and mainstream, while F# offers a more functional programming style on the same .NET platform.

Why use an online C# compiler?

An online C# compiler, also called a C# playground or .NET sandbox, lets you compile and run C# code directly in your browser without installing Visual Studio or .NET. This is ideal for learning C# syntax and .NET APIs, practicing object-oriented patterns, experimenting with LINQ queries, and testing algorithms for coding interviews and academic coursework.

myCompiler's online C# IDE runs the .NET runtime and supports modern C# features including records, nullable types, async/await, LINQ, and the .NET base class library. Write multi-file programs, provide stdin input, and save and share your code via URL, completely free.

Why is C# so popular?

C# has grown from a Windows-only language to a versatile cross-platform powerhouse. Its Unity game engine integration has brought millions of game developers to the language. ASP.NET Core's performance (consistently topping web framework benchmarks) has made C# a serious choice for high-performance web services. Combined with Microsoft's investment in Blazor (C# in the browser via WebAssembly) and .NET MAUI for mobile, C# covers an remarkably broad range of platforms.

C# career opportunities

C# developers are in demand for software engineer, .NET developer, game developer, full-stack developer, and cloud engineer roles. Microsoft's enterprise dominance means C# jobs are plentiful in large corporations and the Microsoft partner ecosystem. Unity game developer is a growing specialization, and ASP.NET Core's performance has driven C# adoption in high-throughput backend services.

Try C# online Free · No sign-up needed

Keyboard shortcuts

Code faster with these keyboard shortcuts in the myCompiler editor.

Run code

+ Enter

Save program

+ S

Toggle comment

+ /

Indent line

Tab

Unindent line

Shift + Tab

Undo

+ Z

Select next occurrence

+ D

Find & replace

+ H

Embed the C# compiler on your website

Add an interactive C# compiler to your website, blog, or learning platform. Readers can write and run C# code directly on your page without leaving it.

Perfect for technical tutorials, coding courses, documentation, and educational content. Save a program on myCompiler and use the embed link to add it to any webpage.

Embedded C# compiler, editor and code runner

HTML

<iframe
src="https://www.mycompiler.io
    /embed/csharp"
width="100%"
height="400"
frameborder="0">
</iframe>

Why developers choose myCompiler

A full-featured online IDE for C# and 27+ other programming languages.

27+ Languages

Python, JavaScript, Java, C++, Rust, Go, TypeScript, C#, and many more. All compilers and interpreters in one place. Switch languages instantly.

Dark & Light Mode

Switch between light and dark themes with one click. Code comfortably in any lighting condition, day or night.

Mobile Friendly

Fully responsive editor optimized for phones, tablets, and Chromebooks. Code on any device with a web browser. No app download needed.

Save & Share Code

Save programs to your account, share via unique URLs, and let others view, fork, and run your code. Great for collaboration and code reviews.

Tags & Organization

Organize your saved programs with tags and find them quickly with search and filters. Build a personal library of code snippets and solutions.

No Account Required

Start writing and running code immediately. No sign-up, no email, no credit card. Create a free account later only if you want to save your work.

Explore more programming languages

myCompiler supports 27+ languages. Switch between them anytime. All free, all in one place.

View all 27+ languages

Frequently asked questions

Common questions about using the online C# compiler, playground, and code runner.

Yes! myCompiler is completely free for all supported languages including C#. There are no subscriptions, no premium tiers, and no hidden costs. Every feature is available at no charge.

myCompiler keeps its C# environment up to date. You can see the exact version on the language details section of this page. We regularly update all language runtimes to their latest stable versions.

Yes. myCompiler runs C# using the .NET runtime, supporting modern language features like LINQ, async/await, pattern matching, and records. You can use the .NET standard library in your programs.

Simply open the C# editor, write or paste your code, and click the Run button. Your code will be executed on our servers and the output will appear in the terminal panel within seconds.

Yes. Click Save to store your program. You will receive a unique URL that you can share with anyone. Recipients can view, fork, and run your code.

Yes. myCompiler supports multi-file projects. You can create, rename, and delete files in the sidebar. This lets you organize your C# code just like in a local IDE.

Yes. All code runs in isolated containers on our servers. Each execution gets its own sandboxed environment that is destroyed after completion. Your code cannot affect other users or our infrastructure.

Yes. myCompiler has a responsive design optimized for phones and tablets. You can write and run C# code on the go. The mobile interface uses tabs for switching between the editor, output, and file panels.

Yes. Click the Input tab in the bottom panel, type or paste your input data, then click Run. Your program will read from the input you provided.

Execution is fast. Code runs on our optimized cloud infrastructure and output typically appears within seconds. Execution time depends on the complexity of your program.

Yes. myCompiler provides an embed feature. You can copy an iframe snippet and paste it into your website, blog, or documentation. Visitors can edit and run code directly on your page.

myCompiler supports common editor shortcuts including Run (Ctrl/Cmd+Enter), Save (Ctrl/Cmd+S), Find (Ctrl/Cmd+F), and more. See the keyboard shortcuts section on this page for the full list.

No. myCompiler requires an internet connection because code is compiled and executed on our cloud servers. The editor itself loads in your browser, but running code requires connectivity.

myCompiler offers a fast, free, zero-setup environment with a modern code editor, multi-file support, dark mode, and instant sharing. It is ideal for learning, prototyping, interviews, and sharing code examples.

Yes. myCompiler is great for practicing algorithms and coding problems. You can write C# code, provide custom input, and test your solutions instantly. Save your work and come back to it anytime.

Use print statements or console output to trace your program's behavior. myCompiler shows all standard output and error messages in the terminal panel. Error messages include line numbers to help you locate issues.

Ready to write C# code?

Open the free C# playground and start coding immediately. No downloads, no account required.

Start coding in C#

Free · No sign-up required · Mono 6.8.0