Additional prompt details

Ebay is a multinational e-commerce corporation, facilitating online consumer-to-consumer and business-to-consumer sales. The website is free to use for buyers, but sellers are charged fees for listing items and again when those items are sold. The sellers aution their items and buyers bid on items.

Functional requirements (FR)

• Create and manage the primary transaction or listing lifecycle from initiation through completion or cancellation.
• Support lookup of current status, transaction history, and the parties or items involved.
• Apply domain rules for pricing, eligibility, inventory, settlement, or auction outcomes as stated in the prompt.
• Provide auditable records for user actions and externally visible state changes.

Non-functional requirements (NFR)

• Prevent duplicate or conflicting transactions under retries and concurrent requests; define the required consistency boundary.
• Protect account, payment, and transaction data with authentication, authorization, encryption, and auditable access.
• Set explicit latency and availability targets for read and write paths, including degraded operation during dependency failures.
• Define reconciliation, recovery, and retention objectives for financial or order records.

Principal-level discussion

• Define the scale, success measures, and operational ownership before committing to an architecture.
• Compare at least two viable approaches and explain the trade-offs, migration path, and failure behavior.
• Identify the riskiest assumptions and how you would validate them with data or a staged rollout.