Talk in three words: types, static-code-analysis, Gradualizer Abstract Type systems and gradual typing is beautiful and a type checker for Elixir that finds all type errors at compile time would be very useful. Putting the theory aside, Peter will explore the everyday difficulties of implementing such a type checker and testing it properly. Objectives After this talk attendees will value the many years of development and discipline that was put into Dialyzer and also see what added-value Gradualizer can bring. Audience Developers interested in type-checking. The speaker Peter spent quite a few years at Ericsson where he became an Erlang native. Later he utilised his experience in various other industries from sports-betting to online ad servers at Erlang Solutions. Recently, he has joined Appliscale to fight cloud-scale systems. Github: gomoripeti ElixirConf EU Website: www.elixirconf.eu Twitter: www.twitter.com/elixirconfeu Mail: info at elixirconfeu