A component is a set of functions, data structures, and algorithms that solve one problem. This means that all the code and artifacts that are used to build the component have a high cohesion with each other; the rule here is that the classes or files that create a component should change at the same time and for the same reason.

Software architecture is built using many components, and you should not be worried about having an excessive quantity of these. The more components you write, the more freedom there is to assign them to different developers or even to different teams. Large software architectures can be created using many smaller components that can be developed and deployed independently of each other.

Once we connect these components to each other, they allow us to create the desired software architecture.

As shown in the following diagram, we can see the components as pieces of a puzzle that come together to form an application:

The connected components define application architectures, and their designs describe how each component has been created internally. It's here that pattern designs and SOLID principles must be used to create good designs.