UD (Trading Business) Pekanbaru Jaya, a goods distribution store, often experiences problems in monitoring supplier stock and ordering goods, resulting in stockouts and operational inefficiencies. This study aims to design and implement an effective and efficient stock monitoring system by utilizing the Collaborative Filtering method. This method was chosen because of its ability to predict goods preferred by users based on the opinions of other users, so that it can provide accurate recommendations even though the content information is limited. This system will also use the Waterfall model in its development, which ensures that each stage of development is carried out in a structured and well-documented manner. The results obtained in this study are the creation of a website-based application to manage supplier stock at UD (Trading Business) Pekanbaru Jaya so that with this application it can help to monitor stock and also with the recommendation system implemented in it can help buyers in choosing goods. This implementation is expected to help UD. Pekanbaru Jaya in managing assets and inventory, ensuring sufficient availability of goods, reducing the risk of stockouts, and optimizing resource utilization. The results of this study indicate that the developed system is able to increase efficiency in managing stock and provide a better shopping experience to customers through online stores.