Functional requirements (FR)

• Ingest or maintain the source data required for the requested search, ranking, analytics, or alert behavior.
• Let authorized users query results using the filters, time ranges, or preferences in scope.
• Refresh derived results as source data changes and expose freshness or confidence where relevant.
• Provide controls for subscriptions, thresholds, or saved views where requested.

Non-functional requirements (NFR)

• Set measurable freshness, query-latency, and throughput objectives.
• Define correctness bounds for aggregation, ranking, deduplication, and late-arriving data.
• Protect user and event data and enforce tenant access boundaries.
• Make data lag, query failures, alert delivery, and cost visible to operators.

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.