Data Engineering Interview Kit 2026 – Basic (PDF)

Launch offer: 25% off with code LAUNCH25 until 18 October 2026, 21:00 CEST (Basic €14.25 instead of €19).

80 data engineering interview questions with model answers, trade-offs, common mistakes and the follow-ups interviewers actually ask. Plus 10 worked design exercises and a SQL practice set with verified solutions.

Interviews are not decided by the first answer but by the follow-up: "Why ROW_NUMBER and not RANK?", "What happens when that event arrives two days late?", "How would you backfill that safely?" Each of the 80 questions has:

• a short answer you can say in 30 seconds
• for 26 key questions, a "what interviewers listen for" box contrasting a weak and a strong answer
• a deeper explanation with code or a concrete example
• the trade-offs, the common mistakes and at least two likely follow-up questions with answers

Covers SQL (14), Python (9), Spark (12), Data Modeling (12), System Design (10), Airflow 3 (6), dbt (6), CI/CD & IaC (6), Observability & Data Quality (5). 10 worked exercises (clickstream at 1B events/day, CDC with full history, SaaS MRR, cron → Airflow + dbt migration and more). SQL practice set: 15 problems on one dataset, every solution executed with DuckDB and the actual output printed.

PDF, A4, 107 pages, clickable table of contents. Version 1.0.1 · checked against Airflow 3, dbt 1.10, Spark 4 · last updated October 2026.

For junior to mid-level data engineers preparing to switch jobs, and for backend, analytics and DevOps engineers moving into data engineering. Not for complete beginners who have never written SQL.

Want a project to show in interviews? Pro (€39) adds a runnable Airflow 3 + dbt + DuckDB portfolio project, a 14-day study plan and the SQL practice set as files. Upgrade later at any time: email info@itcraftsman.de with your order number and you get a coupon worth the price you paid.

Try first: the free sample with 20 complete questions is in the store: https://payhip.com/b/18A5n

30-day money-back guarantee: if the kit does not help your preparation, email info@itcraftsman.de within 30 days of purchase with your order number and you get a full refund. This voluntary guarantee is in addition to your statutory rights.

Right of withdrawal for digital content. This product is digital content that is delivered immediately after purchase. By completing your purchase you request immediate delivery and acknowledge that your right of withdrawal expires once the delivery (download) has started. Regardless of this, our voluntary 30-day money-back guarantee applies: if the kit does not help your preparation, email info@itcraftsman.de within 30 days of purchase with your order number and you get a full refund. This guarantee is in addition to your statutory rights.

About the author: IT-Craftsman is the company of an independent data engineer and DevOps freelancer who has delivered several data engineering and DevOps projects for large companies. He also works for a technology consulting firm, where he conducts hiring interviews for data engineers and DevOps engineers. Quality: every SQL solution was executed in DuckDB; everything else is checked against the official docs. No testimonials, invented credentials or made-up statistics.

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