---
title: ".cs file — what it is and how to open it"
description: "A .cs file is a C# Source. Source code in C#, Microsoft's language for .NET and Unity games. How to open one on Windows, macOS and Linux, and what to convert it to."
url: https://atoneplace.net/file/cs/
site: "At One Place"
---

# .cs files

**.cs file: C# Source**

Source code in C#, Microsoft's language for .NET and Unity games.

## What opens a .cs file

- **Windows:** Visual Studio, Visual Studio Code, JetBrains Rider, Notepad (built in)
- **macOS:** Visual Studio Code, JetBrains Rider, TextEdit (built in)
- **Linux:** Visual Studio Code, JetBrains Rider, Text Editor (built in)

## What a .cs file is

C# was designed at Microsoft in 2000 and is the main language for .NET applications and Unity game scripting. A .cs file is plain text compiled into an assembly (.dll or .exe) that the .NET runtime executes. Visual Studio is the traditional home, but VS Code with the C# extension works well on all three platforms and .NET itself is cross-platform.

## Converting it

A .cs file is commonly converted to .dll, .exe or .txt. It is a plain text format, so any text editor can open and edit it directly.

## Details

- **Extension:** .cs
- **Full name:** C# Source
- **Category:** Code and scripts
- **Created by:** Microsoft
- **Format:** Plain text

## Common questions

### How do I open a .cs file?

On Windows use Visual Studio; on macOS use Visual Studio Code; on Linux use Visual Studio Code. Source code in C#, Microsoft's language for .NET and Unity games.

### What is a .cs file?

C# Source. C# was designed at Microsoft in 2000 and is the main language for .NET applications and Unity game scripting. A .cs file is plain text compiled into an assembly (.dll or .exe) that the .NET runtime executes.

### Can I convert a .cs file?

Yes. It is usually converted to .dll, .exe or .txt, either by exporting from one of the programs listed above or with a format converter.

## Related pages

- [.html — HyperText Markup Language](https://atoneplace.net/file/html/)
- [.js — JavaScript Source](https://atoneplace.net/file/js/)
- [.css — Cascading Style Sheet](https://atoneplace.net/file/css/)
- [.py — Python Source](https://atoneplace.net/file/py/)
- [.java — Java Source](https://atoneplace.net/file/java/)
- [.tsx — TypeScript Source (JSX)](https://atoneplace.net/file/tsx/)
- [.cpp — C++ Source](https://atoneplace.net/file/cpp/)
- [.php — PHP Source](https://atoneplace.net/file/php/)
- [.c — C Source](https://atoneplace.net/file/c/)
- [.go — Go Source](https://atoneplace.net/file/go/)
- [.rs — Rust Source](https://atoneplace.net/file/rs/)
- [.rb — Ruby Source](https://atoneplace.net/file/rb/)

## Sources

- Media Types Registry — IANA (https://www.iana.org/assignments/media-types/)
- Official vendor product documentation — At One Place (/about/)