Backend is the "inner part" of a website that runs on the server. It processes user requests, interacts with databases, and handles business logic.
Backend developers use languages like Python, PHP, Java, C# (.NET), Node.js, and others. Frameworks such as Django, Spring, ASP.NET, Express.js are also commonly used.
The main task of the backend is to ensure reliable website operation, data storage, and communication between the user and the server.