In this chapter, we will learn about core concepts in Koa, including the application and context objects. We will also dig further into the context object that houses the request and response objects. We will see how Koa provides methods around its request and response facilities.

The concept of middlewares in Koa will also be properly discussed in this chapter. We will introduce and explain middleware definition and functionality in Koa. We will use code examples to show clearly how the flow of logic with middleware works in Koa.

The topics we will cover in the chapter include the following:

• The application object
• The context object
• The request object
• The response object
• Middleware