Red is the web-based editor that is built-in to every Rascal.

(What is the Rascal? It is a small computer that helps scientists control their instruments, artists make interactive art, and engineers connect their projects to the web faster. It's like a Raspberry Pi, but compatible with Arduino shields and with software that makes it easier for normal people to use. More details at rascalmicro.com.)

Red is not a cloud service; the Rascal runs a webserver that hosts Red.

Red is based around CodeMirror, a Javascript editor component. Red adds a file browser, drag-and-drop file upload, and a suite of functionality that is specific to the operation of the Rascal, like the ability to reload the Rascal's Python code on the fly.