Data Engineer Interview Questions
Practice 140 real Data Engineer interview questions for 2026. Covers companies like Meta, TikTok, Rbcroyalbank, Capital One, and Amazon — real Data Engineer interview questions from actual interviews with detailed solutions to help your interview preparation. Expect the loop to emphasize production-grade SQL, scalable ETL and pipeline design, distributed-processing tooling (Spark/Kafka), data modeling for analytics and OLAP, and data-quality/observability trade-offs alongside behavioral and product-sense conversations tied to metrics. What’s distinctive: hiring teams now prioritize shipping reliable pipelines and diagnosing failures in production over pure algorithmic puzzles, so you’ll be evaluated on writing efficient windowed SQL, designing fault-tolerant pipelines, choosing storage and partitioning strategies, and explaining trade-offs around latency, cost, and observability. To prepare, practice timed SQL and Python exercises, sketch end-to-end pipeline designs with concrete components (Airflow, Kafka, S3/BigQuery/Redshift), rehearse STAR stories about ownership and incident response, and run mock interviews that simulate debugging a broken pipeline under time pressure.
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Write queries for follows and bookings
You are given tables/logs from a consumer app. Solve the following independent tasks. Part A — Active following as of a date (SQL) You have a follow e...
Design KPI dashboard tables: retention, weekly rollups, timezone
Question You are designing the analytical data model behind a fast KPI dashboard for a large-scale photo-sharing app. The dashboard is reported daily ...
Find Top Creators and Login Streaks
Solve the following two interview-style tasks. Task 1: Top creators by likes You are given a list of like events for a business-facing creator platfor...
Design config rollout and click aggregation
The system design rounds included two prompts: 1. Global configuration deployment - Design a system that allows engineers to publish configuration ...
Write Transaction Analytics SQL Queries
You are given a credit-card transaction dataset with the following tables. transactions | column | type | description | |---|---|---| | transaction_id...
Implement a DAG task graph
Implement a class TaskGraph to represent a directed acyclic graph of tasks. Support these operations: 1. add_task(task_id: str) -> None: Add a task if...
Design TikTok Data Engineering Systems
You are interviewing for a data engineering role at a large short-video platform. Design and discuss the following systems: 1. Massive video upload pr...
Compute shipping cost with tiered pricing
You are implementing a shipping-cost calculator for an e-commerce checkout. An order contains multiple line items. Each line item has: - country: str ...
Implement Election Report and Banking Pipeline
You are given two independent data engineering coding tasks. Task 1: SQL Election Exit Poll by State Report An election analytics team needs a report ...
Solve two interval array problems
You are given two interval-based tasks from a technical screen for a data engineering role. 1. Merge overlapping intervals - Input: an array of int...
Define metrics and data model for product features
You are interviewing for a full-stack/data-oriented role. For each of the following product areas, answer Product Sense and Data Modeling prompts. Cho...
Model entities for feed content and shares
Scenario You are designing the data model for a social app’s News Feed that shows multiple content types (text, image, short video). Users can interac...
Explain ETL schema changes and ensure integrity
Behavioral / Data Engineering Discussion Prompts You’re interviewing for a Data Engineer role. Answer the following prompts with concrete examples fro...
Describe a challenging project and your role
You are interviewing for a new-grad software role. Answer the following behavioral prompts (BQ) based on one of your internship or project experiences...
Explain impact and partnership
Prepare for a hiring manager interview and a cross-functional partner conversation. Be ready to answer questions such as: - Why do you want to join th...
Describe Resolving Stakeholder Trade-Offs
Tell me about a time when you worked with multiple stakeholders who had different needs or priorities, and you had to create a solution that satisfied...
Write SQL for basic user metrics
You are given a simplified schema for a fictional social app called Nextagram: - users(user_id PK, username, created_at TIMESTAMP) - follows(follower_...
Implement a stack supporting max and popMax
Design a data structure that behaves like a stack but also supports retrieving and removing the current maximum value. Implement a class MaxStack with...
Implement phrase search and JSON path
The coding rounds included two concrete implementation tasks: 1. In-memory document phrase search - You are given a list of documents, each represe...
Explain concurrency and reliability tradeoffs
The non-design fundamentals rounds covered several topics: 1. Thread-safe counter - Implement an AtomicCounter or similar class with increment() an...