Amazon·Software Engineer·Onsite - System Design / Architecture
May 2026
Amazon system design round for a software engineering role, basically one big question about building an online bookstore from scratch. They wanted everything: requirements, APIs, data models, services, storage, scaling. It was a lot to cover in one session.
- Design an online bookstore that supports browsing, searching, and purchasing books. Walk through your full system design including requirements, APIs, data model, and architecture.
- How would you handle inventory reservation and consistency during the checkout flow to avoid overselling?
- How would you ensure idempotency for payment processing and order creation?
- What storage technologies would you choose for the different components of this system, and why?
- How would you approach caching and CDN usage for this bookstore, and what are the tradeoffs?
- How would you design for scalability, availability, and fault tolerance in this system?
- How would you decompose this bookstore into services, and what are the boundaries between them?
- What observability and capacity planning strategies would you put in place for this system?
“This one sprawled fast.” The rest of the author's notes on Software Engineer interview at Amazon, Onsite - System Design / Architecture round, covers how they worked through the question, what the panel pushed back on, and what they would do differently.
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