I would like to introduce the open source Ritzy web-based rich text editor: http://ritzyed.github.io/ritzy/. It is based on React [1] and SwarmJS [2] and primarily intended for embedding into applications to support rich text entry with real-time collaboration. Technically, it works similarly to Google Docs and eschews ContentEditable in favor of a custom javascript-based editor surface and layout engine [3]. As far as I know, this is the first open source implementation of this technique. Please see the project README and source code [4] for more details. Note that this is pretty new and hasn't seen any real-world testing/usage, so there are some known bugs [5] and likely lots of unknown ones as well.

Depending on interest, I am considering offering the editor as a software-as-a-service solution. Because it is intended for real-time collaboration, a server-side component is (currently) required. While a simple implementation is part of the open source project, a more complete commercial service could handle storage, communications, security, availability, and provide a simple but powerful API for developers. The API would allow interaction with client-side editors and the data they contain, including real-time server-side push updates as editor contents change. Please let me know if your company or startup may be interested in such a service.

  [1] https://facebook.github.io/react/
  [2] http://swarmjs.github.io/
  [3] http://googledrive.blogspot.ca/2010/05/whats-different-about-new-google-docs.html
  [4] https://github.com/ritzyed/ritzy
  [5] https://github.com/ritzyed/ritzy/issues