Additional prompt details

• Application has two major things : - The songs, which are cataloged in the app’s data store. Songs can be described by attributes such as genre, tempo, singer. - The people : Each person has a playlist of songs that they can choose to play from.

   - Design a system that recommends a set of songs from our music library to the user based on his preferences (matching genre / singer/ tempo)             taking into account his current playlist.
   - Pick a song based on the following order:
   - One which matches with maximum matching attributes.
   - When only one attribute is matching, pick one in the following order : genre > singer > tempo.
   - To decide priority between two genres\singer\tempo, consider the number of songs in each category in the user's playlist to decide which               song gets more priority. One with a higher number of songs gets high priority. If the number of songs are the same, show in any order.
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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.