Interview questions / Data Engineer
Data Engineer interview questions
These are questions Data Engineer candidates often hear, with a short note on what a strong answer covers. Reading them helps; saying your answers out loud helps more.
Design a pipeline that loads daily sales data into a warehouse.
Cover sources, scheduling, transforms, data checks and what happens on failure.
Batch or streaming: how do you choose?
Tie it to how fresh the data must be, volume and cost.
How do you make a pipeline safe to re-run?
Explain idempotency: upserts, partitions and avoiding duplicate loads.
How do you catch bad data before it reaches a dashboard?
Mention schema checks, row counts, null checks and alerts.
Explain a star schema and when you'd use it.
Describe fact and dimension tables and why analysts find them easy to query.
Tell me about a pipeline you made faster or cheaper.
Give before and after numbers.