Interview prompt
Problem context
A release changes an API, adds database fields, publishes a new event shape, and backfills state. Error rates rise after 30% rollout. Reinstalling the old application may not understand new writes, while reverting the schema could destroy data. Define release and rollback architecture.
Skills being evaluated
compatibility designprogressive deliverydata reversibilityincident judgment
The full reasoning guide is part of Pro
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