In Part II, we’ll explore the features that will help you build a new generation of web applications. You’ll learn to use channels to build highly concurrent interactive applications using a new set of abstractions. Then, you’ll learn to build service layers with the OTP API, the famous Erlang library for building supervised, fault-tolerant services. You’ll manage all of this with Mix, Elixir’s build tool, allowing us to break a single monolithic application into smaller ones, separately maintainable but conveniently integrated. Finally, you’ll learn to test channels and OTP features. You’ll learn to build interactive applications that scale well and are easy to understand.