A CS Cart developer is responsible for customizing and optimizing the CS Cart ecommerce platform to suit business needs. They design and develop functionalities, integrate third-party services, and ensure seamless user experience. Their duties include setting up the platform, implementing security measures, and fixing bugs. They work with databases, servers, and APIs, and use languages like PHP, JavaScript, and HTML. They also handle upgrades, maintain documentation, and provide technical support. Ultimately, a CS Cart developer ensures the ecommerce site runs efficiently, is user-friendly, and meets business goals.