I need a comprehensive buy and sell platform to manage 200k+ items. Key Requirements: - Store functionality to facilitate buying and selling - Categorization of items by product type - User authentication via email and password - Importing prices from Excel to link with items and establish buy/sell prices Ideal Skills and Experience: - E-commerce platform development - Experience with large inventory management - Excel data integration - Strong knowledge of user authentication protocols Please share your relevant experience and approach. Thank you!