This project introduces a Smart Multi-Vendor Billing and Inventory Optimization System aimed at improving efficiency for small-scale retailers. It automates billing, manages inventory in real time, and supports multiple vendors on a single platform. By integrating inventory optimization techniques like EOQ and ABC analysis along with predictive models such as ARIMA and Prophet, the system enables accurate demand forecasting and better stock control. Built on a cloud-based architecture with real-time dashboards, it helps reduce manual errors, prevent overstocking and stockouts, and supports data-driven decision-making, ultimately enhancing business efficiency and sustainability.