CodePen
CodePen is a social development environment. At its heart, it allows you to write code in the browser, and see the results of it as you build.
About
We say social because CodePen is a community. Most creations on CodePen are public and open source. They are living things that other people and the community can interact with, from a simple hearting to leaving a comment, to forking and changing for their own needs.
People use CodePen for all sorts of things: prototyping new ideas, reducing test cases for bugs, sending clients things to look at, evaluating potential hires, to finding inspiration. People also use CodePen as a sort of resume and portfolio, showing off their best design and development work.
We're trying to make CodePen a happy and healthy place for front-end designers and developers and the people looking for them, while also being a damn fine place to code. ❤️