- JS Fiddle - test your JavaScript, CSS, HTML or CoffeeScript online with JSFiddle code editor;
- Playcode - the fastest online code sandbox for quickly and easily make frontend experiments;
- Code Sandbox - instant IDE and prototyping tool for rapid web development;
- CodePen - social development environment for front-end designers and developers;
- JS Bin - live pastebin for HTML, CSS & JavaScript and etc;
- .NET Fiddle - test your C# code online with .NET Fiddle code editor;
- Online C# IDE - online C# IDE;
- Ideone - online compiler and debugging tool;