Wikipedia says this about Cloud9: Cloud9 IDE is an online integrated development environment (IDE), published as open source from version 3.0. It supports hundreds of programming languages, including C, C++, PHP, Ruby, Perl, Python, JavaScript with Node.js, and Go. It enables developers to get started with coding immediately with pre-configured workspaces, collaborate with their peers with collaborative coding features, and web development features like live preview and browser compatibility testing.

Wikipedia goes on to say: It is written almost entirely in JavaScript, and uses Node.js on the back-end. The editor component uses Ace. As of July 2014, it uses Docker containers for its workspaces, and is hosted on Google Compute Engine.

You can write your code here and share it with others and they can edit it.

Cloud9 has changed the way they do signups since they were acquired by Amazon. However, if you are a student of the Udemy course The Web Developer Bootcamp by Colt Steele you can still get an invitation for the original Cloud9 by going here.

Additionally, if you would rather setup your local development environment then you can follow these instructions (made for MEAN stack, but we are just using the MEN portion*) for installing npm, node, and mongodb. Instructions are included for PC (Windows/Linux) and Mac. Windows users can also use some of the articles from Zarko’s blog instead.