Based on your requirement I would think about 2 options for backend (REST service): 1. if I am a single backend developer for some period of time or have 1-2 p

Based on your requirement I would think about 2 options for backend (REST service): 1. if I am a single backend developer for some period of time or have 1-2 people around I would go with what I am most familiar with and what can suit: in my case it is Scala, Playframework, MongoDb or Postgres. 2. If I start with a team to hire and work on the whole stack I would start with something that is both rather hot/new to attract smart developers and keep them motivated and stable, with good stable choice of libraries to focus on the product not fixing issues in half-baked libraries. I believe Node.js MEAN stack or Rails would be my choice. For front-end I would go with Javascript/Angular.js