CodeShare.io - Realtime code sharing for developers
Pastebin.com - Pastebin.com is a website where you can store text for a certain period of time.
Visual Studio Live Share - Real-time collaborative development
CodeChef IDE - CodeChef IDE is a free online tool for developers helping them in writing codes and programs.
Teletype for Atom - Collaborate in real time in Atom
myCompiler - Run your favourite programming languages online