The development of digital technology encourages business entities to utilize e-commerce to expand their market. However, many have difficulty managing financial reports because the online sales system is not yet integrated. Ewilla Sewing, a convection business, still records finances manually and separately from online sales.  This study designs and implements an integrated e-commerce financial management accounting system to improve the accuracy, efficiency, and reliability of financial reports. The research method uses a descriptive qualitative approach with observation, interviews, and document analysis. The system was developed with a waterfall model. The results of the study show that the system is able to manage finances more efficiently, accelerate reporting, provide real-time data, support internal audits, and help make more appropriate decisions for Ewilla Sewing.