Dealing with money should be easy, because crunching numbers is the most basic thing that every computer can do. On the other hand, the cost of a mistake may be quite high. I am going to discuss what properties does a financial system need in terms of CAP theorem and how does using Elixir language fit into the problem domain. The talk will cover handling rounding errors, designing APIs that gracefully handle network and hardware failures, and usage of "let it crash" approach in the design. It is also a case study of using Elixir in real life. Lets discuss Elixir and money!