What do you use scala for?

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.

If you want an at scale scala user, twitter is a huge one.

https://github.com/twitter

Apache Spark is also written in scala. http://spark.apache.org

Scala is used for a lot for systems programming. I personally use the JVM for my distributed machine learning work.

Interesting topic, would love to see more answers here.

I am currently building a web based database management tool in Scala and Backbone.js. Our initial prototype was built in Python, but Scala proved to be multiple times better fit for this kind of project.

Also we now offer both self-hosted and in cloud versions mainly thanks to JVM.

We (PagerDuty, YC S10) use Scala + Cassandra to build distributed services that comprise our realtime infrastructure - receiving alerts from monitoring systems, sending out email/SMS/phone/push notifications and everything in between. High availability is a requirement.

At my last job, we used Scala/Play to essentially generate a complex single-page app composed of dozens of partial templates. It was a technology mismatch and proved to be a controversial decision among the developers.

The Typesafe blog regularly includes case studies to give you some idea of Scala in the wild: http://www.typesafe.com/blog/CaseStudy

TextTeaser (https://github.com/MojoJolo/textteaser). It's an automatic summarization algorithm I created.