Where do I save a users ip to figure out whether they have already voted or not during the session?

I want to prevent multiple votes, thanks. What do I use? Mongo, redis?

Hi @EddieCornelious: any of those should be ok. Redis is normally used for sessions: you might need a long term storage, longer than the session expiration time. In that case, use the DB that you are assuming as your persistent DB instead. If Redis is what you are using, then ok. The DB suggested by FCC for that role is mongoDB.

I suggest you for the exercise something that you would like to use because you want to learn that, but also bear in mind most of the platforms used for deploying the challenges pose constraints to what other applications in cloud you can use for free.

So choose the cheapest ones that you want to use.