strategic role in supporting national economic growth. However, many MSMEs continue to face challenges in managing sales transactions, inventory, and business operations, as these processes are often performed manually or through separate, non-integrated systems. This condition frequently leads to data duplication, information inconsistency, and reduced operational efficiency. This study aims to develop the design of SmartKasir Pro Edition, a web-based information system that integrates Point of Sale (POS) and E-Commerce services into a single omnichannel platform. The study employs the Research and Development (R&D) method, focusing specifically on the system design stage. The research process includes requirements analysis, system flow design, database structure design, user interface design, system architecture design, and the preparation of a testing framework using the Black Box Testing method. The proposed system adopts a client-server architecture by separating the frontend and backend components through RESTful API communication. The proposed technologies include React.js and TypeScript for frontend development, PHP Native for backend development, and MySQL as the database management system. The research results in a comprehensive system design consisting of an administrator dashboard, product management, Point of Sale (POS) transactions, E-Commerce services, customer management, order management, inventory control, product search functionality, and sales reporting integrated within a centralized database. The proposed design of SmartKasir Pro Edition is expected to serve as a reference for future system implementation and further development, while also providing an alternative solution to support business process digitalization and improve the operational efficiency of MSMEs.