Creating a popular cosmetic shopping app like Sephora involves several key steps. Begin with comprehensive market research to understand customer preferences and trends. Develop a user-friendly and visually appealing interface with features like product search, reviews, and personalized recommendations. Secure partnerships with cosmetics brands for a diverse product catalog. Implement secure and convenient payment options. Focus on a robust backend system for inventory management and order processing. Invest in marketing and promotions to attract users, and consider loyalty programs to retain customers. Regularly update the app with new products and features to keep users engaged. Finally, prioritize customer support and feedback to enhance the overall shopping experience and build brand loyalty, aiming to replicate Sephora's success in the cosmetic retail space.