Abstract: E-commerce is an online sales media that allows interaction between sellers and buyers. However, many entrepreneurs in the food and beverage sector, including Cafe Youth, have not implemented e-commerce in their business operations. Cafe Youtme has shortcomings in implementing routine sales, promotions, as well as product and sales management. This research analyzes SWOT to develop how a business works with the UML model, covering 12 diagrams including, payment verification, payment confirmation, and sales data recap. UML also includes a class diagram of Cafe Youtme's e-commerce system with seven classes: Customer, Menu, and Payment. The results of the accuracy and reliability test using the AC1 Gwet calculator show a value of 0.66979, which is included in the "Substantial" category, indicating that recommendations for improving business models and customer presentation are good and can be implemented in their business activities.. Keywords: System Development, UML, SWOT, Gwet's AC1, E-Commerce