The Ledger and the Live Wire
A hard Pipeline Design mock interview question on DataDriven, with an AI interviewer who asks follow-up questions and a hire or no-hire decision at the end.
- Domain
- Pipeline Design
- Difficulty
- hard
- Seniority
- mid
Interview Prompt
We run an online retail marketplace that emits about 2 billion order and refund events a day across 300 million listings. Seller-facing inventory and sales dashboards have to reflect a purchase within seconds, while finance needs an exactly-once daily profit-per-product number that stays correct even when refunds land days after the original order. Data science also wants the full raw event history retained for model training.
How This Interview Works
- Read the vague prompt (just like a real interview)
- Ask clarifying questions to the AI interviewer
- Draw your pipeline on the design canvas: sources, transforms, storage and checks
- Answer the interviewer's follow-up questions, then get a hire or no-hire decision