E-commerce Web App

7 prompts: a product catalog → a shopping cart → real checkout with Paystack → inventory that won't sell what you don't have → an orders view for you → going live.

Storage for product photos, Paystack for real payments, and fast image loading — and when it's worth paying for a dedicated image service.

5 checks: can someone change a price before paying, can two people buy the last item at once, can one customer view another customer's order, does a payment ever get double-counted, can discount codes be abused.