CodeSandbox vs Kobra.io: What are the differences?
CodeSandbox: Online playground for React. CodeSandbox allows developers to simply go to a URL in their browser to start building. This not only makes it easier to get started, it also makes it easier to share. You can just share your created work by sharing the URL, others can then (without downloading) further develop on these sandboxes; Kobra.io: Collaborative "Google Docs" for code. Kobra is the easiest way to collaborate on code quickly with your coworkers, friends or students. With built in video & voice chat, the themes and keyboard shortcuts you're used to and syntax highlighting, you'll feel right at home. We're not trying to be your online IDE, we just want to be the simple online editor you use to collaborate on the fly.
CodeSandbox and Kobra.io can be primarily classified as "Cloud IDE" tools.
CodeSandbox is an open source tool with 7.52K GitHub stars and 931 GitHub forks. Here's a link to CodeSandbox's open source repository on GitHub.