# Auth

We use Auth to represent both authentication (AuthN) and authorization (AuthZ).

Cloud development involves Auth, it's unavoidable in our development. Because we need to call cloud APIs, whether it's AWS, GCP or EKS. These APIs are all protected by AuthN and AuthZ. And since the Auth is almost the first obstacle we encounter when we are developing cloud applications, this chapter is very important and it's a must read chapter.

As for other third-party SaaS services, they usually have a simpler Auth model, so we won't discuss them in this chapter.