At my current company, relayr, we use Scala Spray for building infrastructure API, that our internal and third-side apps will use (user management, app, device

At my current company, relayr, we use Scala Spray for building infrastructure API, that our internal and third-side apps will use (user management, app, device management). Our main functionality, reading and processing data from a large number of sensors, is currently built with Node.js, and it's mainly IO, not CPU now. After release we think to gradually move data processing and filtering to Scala / Akka. At my previous startup we used Scala with Unfiltered and Akka for processing lots of data from recipe sites and food stores (NLP stuff, scrapping, retrieving ingredients, matching ingredients with goods etc.), Play framework was also used for admin board and marketing backend. I personally use Scala / Akka to learn about distributed programming, concurrency, compiler and DSL building etc.