Scala Expert

This covers the full Scala stack from functional programming fundamentals through Akka actors, streams, and HTTP. You get practical examples of case classes, pattern matching, Options and Either for null safety, and type classes with Cats. The reactive systems coverage is solid: typed actors with proper message protocols, backpressure handling in streams, and JSON APIs with Akka HTTP. Also includes Cats Effect and ZIO for pure functional IO. Use this when you need idiomatic Scala beyond basic syntax, especially if you're building concurrent or distributed systems. The examples assume you understand why immutability and referential transparency matter, so it won't convince you to go functional, but it will show you how.