ECommerce

How Would You Design an E-Commerce Checkout Flow?

An e-commerce checkout is designed as a short-lived, stateful order flow that reserves inventory optimistically, computes pricing and tax atomically at the mom…

How to Design a Shopping Cart Service

A shopping cart service stores per-user line items in a fast, durable key-value store keyed by cart ID, merges anonymous and logged-in carts on login, revalida…

How to Design a Coupon System

A coupon system stores codes and their rules (discount type, eligibility, usage caps) separately from redemption records, validates each redemption against rem…

How to Design a Review and Rating System

A review and rating system stores individual reviews as immutable, append-mostly records tied to a verified purchase or interaction, maintains a precomputed ag…