How to: API design
Next, we can start designing APIs for the system. These APIs will help us define the expectations from the system explicitly. We don't have to write any code, just a simple interface defining the API requirements such as parameters, functions, classes, types, entities, etc.

For example:

```tsx
createUser(name: string, email: string): User
```

It is advised to keep the interface as simple as possible and come back to it later when covering extended requirements.