The rapid growth of e-commerce has transformed consumer shopping behaviors, making it essential to understand the factors that influence online shoppers' purchase decisions and satisfaction levels. This study investigates the key determinants such as website usability, product variety, price competitiveness, trust and security, customer reviews, and delivery efficiency that affect consumer behavior in online marketplaces. Using a mixed-method approach combining surveys and interviews, data was collected from a diverse group of online shoppers. The findings reveal that trust in the platform, ease of navigation, and the perceived value of products significantly impact purchase decisions, while prompt delivery and responsive customer service play critical roles in shaping overall satisfaction. Additionally, the study highlights the mediating role of customer satisfaction in the relationship between purchase experience and brand loyalty. The insights gained can help e-commerce businesses refine their strategies to enhance user experience, build customer trust, and drive higher satisfaction and repeat purchases.