CodeOcean is described as 'Code Ocean is a cloud-based computational reproducibility platform that provides researchers and developers an easy way to share, discover and run code published in academic journals and conferences'. There are five alternatives to CodeOcean, not only websites but also apps for a variety of platforms, including Android, Chrome OS, Android Tablet and Mac. The best alternative is Plunker, which is both free and Open Source. Other great sites and apps similar to CodeOcean are kodeWeave (Free, Open Source), Spck Editor (Free), Codenvy (Freemium) and codeboard.io (Free).
Codeboard.io is a web-based IDE to teach programming in the classroom. Easily create and share exercises with students. Analyze and inspect students' submissions with a single click. Create exercises in a feature-rich IDE and simply share them using their Urls.