This is a lot of ground to cover and I underestimated how much they'd actually want to dig into each layer.
Choose a real ETL pipeline you built and narrate it as a story with clear phases: business context, architecture, and operations. Focus on the decisions and trade-offs you made, especially around failures, schema changes, and backfills, to show engineering maturity. Keep the narrative structured and end with measurable impact.
Pro tip: Emphasize how you made the pipeline idempotent and how you handled schema evolution without breaking downstream consumers—these are the details that separate senior engineers from juniors. Also, quantify the impact (e.g., reduced latency by X%, saved Y hours) to make your answer memorable.
Briefly describe the business goal, the source systems, and the data volume/velocity. Explain why the pipeline was needed and what value it delivered.
Explain how data was ingested (batch vs. streaming, tools used) and the key transformations applied. Highlight any complex logic or data quality checks.
Discuss the data model (e.g., star schema, normalized) and why you chose it. Describe the orchestration tool (e.g., Airflow, Dagster) and how dependencies were managed.
Detail your testing strategy (unit, integration, data quality), monitoring/alerting setup, and how you handled failures, retries, and backfills.
Explain how you managed schema evolution (e.g., Avro, schema registry) and the impact of your work (e.g., performance, cost, business metrics).
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.
Choose a specific example where you faced ambiguity or conflict, and structure your answer using the STAR method. Focus on how you gathered data, communicated with stakeholders, and drove alignment toward a solution that balanced technical and business needs.
Pro tip: Emphasize how you used data and user impact to resolve disagreements, and show that you can disagree and commit even when your preferred approach wasn't chosen.
Briefly describe the project, your role, and the source of ambiguity or conflict (e.g., unclear requirements, stakeholder disagreement, technical debate).
Detail the steps you took to understand the problem, such as gathering requirements, researching options, or facilitating discussions.
Describe how you navigated the disagreement, including how you listened to others, presented data, and built consensus.
Share the positive results of your actions, such as delivering the project on time, improving team alignment, or achieving business goals.
Conclude with what you learned from the experience and how it has improved your ability to handle similar situations in the future.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.