As part of application architecture, there will be both frontend and backend services. Frontend development is concerned with the user experience of the app. In contrast, backend development focuses on providing access to the data, services, and other existing systems that make the app work. In short, the frontend is what the user interacts with (e.g., mobile app or web page), and the backend is the blackbox, which the users do not see, does all the heavy lifting of managing data and processing user requests.