Pretty straight forward, went for the simplest solution (Socket.io), wrapped it with Google Auth for login and user name, not enough time (still employed) to write database interaction so used a Node.js version of localstorage (flat file storage). Wrapped the whole thing as a docker image to easily deploy on AWS (which I did) and implemented scripts to deploy with Swarm Kit for an example scaled solution. You must pick between several fixed titles for the essay, it should be 750-5000(!) words. I wrote around 1000 words given the time I had left. Reply from recruiter was that technical skill was not enough. No technical feedback.