This chapter covers a lot of practices and hacks to make the whole stack of the demo project, a mobile payment system, work. Please go through the content of all the sections in this chapter:

1. Why do we need to hack the Fn to build a custom version of an Fn server?
2. What is the concept of inter-FaaS platform networking? Why is it important?
3. What are the two roles of an Ethereum block in the demo project?
4. What is the data type of the parameters of an OpenWhisk function?
5. How can we encode JSON in Java with Fn?
6. How can we encode JSON in Golang?
7. What is the Parse platform?
8. What is the role of Parse WebHook?
9. What is the concept of a Glue function?
10. How can we write a function to wrap a legacy web-based application?