Thimble by Mozilla

CodeBunk is a flexible and collaborative compiler that makes the process of sharing your code with friends and testing potential job applicants simple.

JsFiddle is a cloud-based JavaScript code playground that allows web developers to tweak their code and see the results of this tweaking in real time. The editor supports not only JavaScript

JSitor is a cloud-based code playground that allows web developers to write/share the web snippets as well NodeJS snippets. This supports almost all mainstream JavaScript, CSS and HTML frameworks.

Powerful and simple online compiler, IDE, interpreter, and REPL. Code, compile, and run code in 30+ programming languages: Clojure, Haskell, Kotlin (beta), QBasic, Forth, LOLCODE, BrainF,