C# Online Compiler
Write, compile, and run C# online in a fast, isolated sandbox. No setup, no sign-up, free.
Run C# online, no setup
Write C# in the editor above, press Run, and your program executes in a fast, isolated sandbox, right in your browser. No installs, no configuration, and no account required to run code. Switch languages anytime from the rail on the left.
Features
- ✓Instant run with stdin support
- ✓Syntax highlighting & line numbers
- ✓Resizable, switchable editor / output layout
- ✓A built-in shared whiteboard for sketching ideas
- ✓AI help to explain, debug, and improve your code (Premium or your own OpenAI key)
- ✓Invite friends to code together live (free)
Compiler plus developer reference
Use the editor for quick experiments, then open the C# cheatsheet when you need syntax, examples, and common patterns. Hack University also keeps a free developer reference library and public software engineering courses for deeper practice after a snippet works.
Want to go further?
Hack University is a selective, all-in-one platform for becoming a software engineer: a full computer-science curriculum, hands-on practice, and career tools. The online compiler is free and open to everyone.