Codesandbox.io: Great for React, cannot accept POSTs
Codepen.io: Great for CSS, though it does support React, JS, HTML & Pug
For just frontend deployment, see now.sh & netlify. Really quick simple deployments now.
#Fullstack (include a VM/Container for development)
Stackblitz: VSCode in the Cloud
C9.io: Was really nice, but it’s been bought by Amazon; not free anymore, unless you use AWS 😭
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