Design a Game Store with Purchases, Downloads, and Reviews

Design an application or game store with several user-facing pages. Users must be able to browse all games by category, purchase a game and download it, and add reviews.

Describe the user flows, data model, APIs, and backend behavior needed to make those features work consistently.

Constraints and Clarifying Questions

• Clarify catalog size, traffic, download sizes, supported clients, and availability requirements. No numerical scale is supplied.
• Establish when a purchase grants download access and what evidence confirms payment.
• Clarify who may review a game, whether reviews can be edited, and whether purchases affect review eligibility.
• Treat pricing, refund behavior, and download-access duration as product policies to define rather than assume.

Part 1 — Browse the Catalog

Design the category browsing and game-detail experience, including navigation between pages and the data required to render them.

What This Part Should Cover

• Games, categories, and their relationships.
• Stable ordering, pagination, and appropriate catalog caching.
• A clear path from the catalog to a game's details and purchase action.

Part 2 — Purchase and Download

Explain how a user buys a game, sees the purchase outcome, and downloads a game they are entitled to access.

What This Part Should Cover

• Order and payment state, including retries and uncertain outcomes.
• A durable entitlement tied to confirmed purchase state.
• Authorization for downloads and efficient delivery of large artifacts.

Part 3 — Add and Display Reviews

Design review creation and display. Explain the policy decisions and the consistency needed when users submit or edit reviews.

What This Part Should Cover

• Review ownership, eligibility, and storage.
• Validation, repeated submissions, and basic handling of abusive content.
• Pagination and any consistency trade-off between accepted reviews and cached displays.