Data engineering system design interview questions

Data engineering interviews test whether you can move, model and trust data at scale. These rounds cover star-schema and slowly changing dimension warehouses, change data capture, real-time analytics and ad click aggregation, sessionization, IoT telemetry, log pipelines, lakehouses, reusable ETL and ELT frameworks, payments reconciliation, A/B test analytics, data quality and user data deletion.

You design the pipeline end to end, from sources and ingestion through storage, transformation and serving, and explain the guarantees you chose: batch or streaming, exactly-once or at-least-once, freshness versus cost.