SageMathCloud (https://cloud.sagemath.com https://cloud.sagemath.com) has similar functionality (collaborative editing, preview) and supports restructured text.

SageMathCloud (https://cloud.sagemath.com https://cloud.sagemath.com) has similar functionality (collaborative editing, preview) and supports restructured text. To try it, create an account, project, and new file that ends in .rst. It renders the rst server-side using rst2html in Linux, so isn't instant (since not in Javascript) -- are there any good rst to html converters written in Javascript? SMC also runs aspell (server side) when the file is saved. Here's a screenshot: http://wstein.org/misc/smc-rst.png http://wstein.org/misc/smc-rst.png of https://cloud.sagemath.com/projects/4a5f0542-5873-4eed-a85c-a18c706e8bcd/files/support/2015-03-25-061533-hacker-news.rst https://cloud.sagemath.com/projects/4a5f0542-5873-4eed-a85c-... (Disclaimer: I started SageMathCloud and SageMath. SageMath uses Sphinx for documentation, hence we care about RestructuredText editing.)