How would you approach designing a large-scale e-commerce system?

Start with requirements and workload: catalog size, search traffic, order rate, payment flow, inventory consistency, geography, availability, and latency targets. Then identify bounded capabilities such as catalog, cart, ordering, payment, inventory, shipping, and notification.

Choose architecture from the requirements rather than starting with microservices. Define data ownership and consistency boundaries, cache read-heavy data, use durable asynchronous workflows where appropriate, and design observability, security, idempotency, failure recovery, and deployment from the beginning.