Interfaces in PHP are used to define a contract or a blueprint for classes. They provide a way for developers to define a set of methods that a class must implement. The practical usages of interfaces in PHP are as follows:



Abstraction: Interfaces help in abstraction, which means they allow you to define a set of methods that a class must implement, without worrying about the implementation details.

Polymorphism: Interfaces in PHP allow you to create objects of different classes that implement the same interface. This makes it possible to create code that is more flexible and easier to maintain.

Dependency injection: Interfaces are often used in dependency injection to inject objects into a class. This allows you to write more flexible and reusable code.

Unit testing: Interfaces in PHP make it easier to write unit tests, as you can mock the behavior of the interface methods and test the class that implements the interface.

Code organization: Interfaces help in organizing your code by defining a clear set of methods that a class must implement. This makes it easier to understand the code and to maintain it over time.

API development: Interfaces are commonly used in API development to define the endpoints and methods that the API exposes. This helps in building a more modular and extensible API.

Overall, interfaces in PHP provide a way to define a contract between classes and make it possible to write more flexible, reusable, and maintainable code.