What are some alternatives?
JS Bin - Sample of the bin:
Plunker - Plunker is an online community for creating, collaborating on and sharing your web development ideas.
CodeSandbox - Online playground for React
kodeWeave - HTML/CSS/JS and Markdown Code Playground For Web Designers and Developers
Pastebin.com - Pastebin.com is a website where you can store text for a certain period of time.