Interview prompt
Problem context
The same payout can originate from an API, scheduled batch, queue redelivery, or partner callback. Different teams generate different deduplication keys, TTLs expire inconsistently, and a replay once created duplicate payouts. Design an end-to-end idempotency model.
Skills being evaluated
operation identitytransactional deduplicationoutcome semanticscross-team contracts
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The scenario and evaluation focus above remain public. Pro unlocks the structured answer, trade-off analysis, follow-up probes, common weak answers, rubric, related reasoning, and any architecture diagram.
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Clarify the decision
Establish scale assumptions
Functional and non-functional requirements
High-level architecture
Data model and flow
Consistency and transaction boundaries
Failure modes and recovery
Security and privacy
Observability and SLOs
Capacity and cost
Alternatives and trade-offs
Evolution and migration
What Staff and Principal candidates should emphasize