The main difference between frontend and backend development lies in their respective focuses and responsibilities. Frontend development refers to the part of web development that deals with the user interface and user experience, utilizing languages like HTML, CSS, and JavaScript to create visually appealing and interactive websites. In contrast, backend development involves server-side programming, databases, and application logic, ensuring that the frontend operates smoothly. Backend developers use programming languages such as Python, Ruby, or Java, and work with databases like SQL or NoSQL to manage data and server operations.