You need a solid understanding of server-side programming, database management, and system architecture. Proficiency in programming languages such as Java, Python, or PHP is crucial, as is familiarity with server-side frameworks like Node.js, Django, or Flask. Strong problem-solving skills, attention to detail, and the ability to optimize code for performance are essential. Additionally, knowledge of version control systems (e.g., Git), security best practices, and cloud platforms (e.g., AWS, Azure) can be highly beneficial.