Backend programming language. Java, Python, PHP, C #, etc., each language has its own advantages, disadvantages, and applicable scenarios. You can choose the appropriate language based on personal interests and needs. Backend framework. Such as Spring Boot, Django, Laravel http://ASP.NET These frameworks can help quickly build backend applications, providing commonly used functions and components such as routing, templates, database operations, caching, security, etc. database Familiar with SQL statements, data models, indexes, transactions, etc., databases are essential tools in backend development. They can store and manage user and business data, and suitable database types need to be selected according to different scenarios, such as relational databases (MySQL, Oracle, etc.), non relational databases (MongoDB, Redis, etc.), or mixed use.