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Data Engineer Interview Questions
Practice 9403 coding, system design and machine learning questions from 546 companies, sorted by role, topic and interview round. Every question has step-by-step hints, a code runner that supports 8 languages and an AI mentor; members also get the full solution walkthrough.
- 9403
- Questions
- 546
- Companies
- 11
- Topics
- 8
- Languages
Showing 1–30 of 129 results
- AgodaEasyData EngineerCount Integers That Appear Exactly Once
Count distinct integers with frequency exactly one using complete occurrence counts, including empty arrays and separated duplicates.
Coding & AlgorithmsTechnical Screen - AgodaEasyData EngineerFind the Longest Calendar-Day Streak with All Employees Present
Identify dates when every employee is present and compute the longest consecutive streak, treating missing attendance as a gap.
Data Manipulation (SQL/Python)Technical Screen - AgodaEasyData EngineerRank Customers by Monthly Revenue with Competition Ties
Aggregate customer revenue by month and return top competition ranks, preserving tied totals and deterministic display order.
Data Manipulation (SQL/Python)Technical Screen - AgodaEasyData EngineerReturn Every Employee with a Mapped or Default Unique ID
Join employees to unique-ID mappings while preserving unmatched employees and applying an explicit fallback identifier.
Data Manipulation (SQL/Python)Technical Screen - AirbnbMediumData EngineerCalculate the Median House Price in Each City
Tests your ability to compute grouped medians in PostgreSQL, properly handling even and odd row counts, duplicate price values, and numeric precision.
Data Manipulation (SQL/Python)Onsitesqlpostgresqlaggregations - AirbnbMediumData EngineerEstimate Page-Visit Duration from the Next User Event
Implement logic to compute user page-visit durations based on adjacent event timestamps, deterministically resolving ties and handling boundary conditions for terminal events.
Data Manipulation (SQL/Python)Onsitepythonsqldata-manipulation - AirbnbMediumData EngineerFind Hosts Meeting Listing, Rating, and Review-Coverage Rules
Tests the ability to write a SQL query performing multi-table aggregations, date-windowed conditional logic, and host-level qualification filtering across listing counts, average ratings, and recent review coverage.
Data Manipulation (SQL/Python)Onsitesqlaggregationconditional-logic - AirbnbMediumData EngineerFind Users with Seven Consecutive Impression Days
Tests your ability to identify consecutive calendar-day activity streaks in PostgreSQL using window functions, date arithmetic, and deduplication.
Data Manipulation (SQL/Python)Onsitesqlpostgresqlwindow-functions - Akuna CapitalMediumData EngineerCompute Graph Spread and Portfolio Trades
This problem tests graph traversal (connected components) and hash-map manipulation to calculate net delta changes in portfolio assets within identified groups.
Coding & AlgorithmsOnline AssessmentGraphDFS/BFSHash Map - Akuna CapitalMediumData EngineerWrite February Resource Usage Query
This question tests the ability to join multiple tables, handle date filtering with range conditions, and perform grouped aggregations to calculate average metrics across different resource categories.
Software Engineering FundamentalsOnline AssessmentSQLAggregationJoins - AmazonEasyData EngineerAnswer Amazon Behavioral Questions
Three classic Amazon final-round behavioral questions — a significant challenge you overcame, motivating a struggling team, and why Amazon — answered with the STAR framework and Amazon Leadership Principles. Each answer emphasizes ownership, problem solving, collaboration, and quantified impact.
Behavioral & LeadershipTechnical Screen - AmazonMediumData EngineerDescribe past NLP work and collaboration
This question evaluates a candidate's technical expertise in applied NLP methods, data engineering competencies, and collaborative leadership in managing annotation workflows, along with their ability to articulate specific contributions, trade-offs, and metrics from past projects.
Behavioral & LeadershipTechnical Screen - AmazonEasyData EngineerSolve Two String Problems
This task evaluates string manipulation and encoding for generating unique Morse representations, along with sentence segmentation and combinatorial enumeration for producing all valid word-break sentences, focusing on transformation, deduplication, and decomposition skills.
Coding & AlgorithmsTechnical Screen - AppleMediumData EngineerDesign TikTok Data Engineering Systems
This problem tests the ability to design an end-to-end data pipeline for high-throughput mobile app event logging, focusing on ingestion, transformation, and storage optimization.
System DesignTechnical ScreenData PipelinesDistributed SystemsOLAP - AppleHardData EngineerDiscuss Challenges and Career Goals
This question evaluates problem-solving, technical depth, communication, leadership, and career-motivation competencies relevant to a Data Engineer role within the Behavioral & Leadership category.
Behavioral & LeadershipTechnical Screen - AppleHardData EngineerEncode and Rebuild a Binary Tree
This question evaluates skills in data structure serialization and deserialization, binary tree representation, and algorithmic design for deterministic data formats.
Coding & AlgorithmsTechnical Screen - AppleEasyData EngineerImplement most_frequent_key without using max()
This question evaluates proficiency in Python fundamentals and object-oriented inheritance, focusing on frequency aggregation using a precomputed dictionary, iteration over mappings, and correct handling of ties and empty inputs.
Coding & AlgorithmsTechnical Screen - BasetenMediumData EngineerDesign a Data Pipeline for Messy Pod Alerts and Bad Pod Detection
Prepare for a Baseten system design interview about design a data pipeline for messy pod alerts and bad pod detection. This question focuses on requirements, architecture, trade-offs, reliability, and follow-up discussion areas.
System DesignTechnical Screen - BlackRockMediumData EngineerSolve two interval array problems
This question evaluates proficiency with array and interval-manipulation concepts—specifically sorting, merging overlapping ranges, and robust edge-case handling in interval operations.
Coding & AlgorithmsTechnical Screen - BloombergMediumData EngineerImplement RotatingFileSink in hierarchy
This question evaluates a candidate's proficiency in Python object-oriented design, file I/O and JSON serialization, concurrency control via locking, context manager protocols, custom exception handling, and adherence to Liskov substitution when implementing a rotating file sink.
Software Engineering FundamentalsTechnical Screen - BloombergMediumData EngineerImplement classes within an abstract Python framework
This question evaluates a candidate's skills in object-oriented design, implementing concrete classes from abstract interfaces, file I/O and streaming data transformations, error handling, and integration with a registry and CLI within a Python codebase.
Coding & AlgorithmsTechnical Screen - BloombergMediumData EngineerWrite PostgreSQL string-manipulation query
This question evaluates proficiency in PostgreSQL string manipulation, regular expressions, URL parsing, key-value parsing and timestamp-based filtering for data transformation tasks.
Data Manipulation (SQL/Python)Technical Screen - ByteDanceMediumData EngineerChoose Components for a Data Warehouse
This question tests the ability to distinguish between distributed data processing frameworks, storage engines, and relational databases, evaluating your understanding of trade-offs in large-scale data infrastructure.
Software Engineering FundamentalsHR ScreenData EngineeringDistributed SystemsData Warehousing - ByteDanceMediumData EngineerConnect Points With Minimum Total Distance
This problem tests your ability to model a geometric optimization task as a Minimum Spanning Tree (MST) problem and implement it efficiently using Kruskal's or Prim's algorithm.
Coding & AlgorithmsOnsiteGraphsMSTGeometry - ByteDanceMediumData EngineerDesign a Data Service for Downstream Consumers
Design a centralized, governed data serving platform that provides downstream consumers with stable query APIs, schema evolution safety, cursor-based exports, and data freshness metadata.
System DesignHR ScreenData EngineeringAPI DesignData Governance - ByteDanceHardData EngineerMaximize watch time under adjacency constraint
This Coding & Algorithms question for a Data Engineer role evaluates dynamic programming and sequence-optimization skills by requiring selection of a subsequence under a pairwise adjacency constraint on video durations, at a moderate-to-advanced algorithmic abstraction level.
Coding & AlgorithmsTechnical Screen - ByteDanceMediumData EngineerModel Data for Analytics, Reporting, and Applications
Tests your ability to process raw semi-structured event logs into a clean, dimensional metric table suitable for downstream analytics and reporting.
Data Manipulation (SQL/Python)HR ScreenData ManipulationData ModelingPython - Capital OneMediumData EngineerAnswer conflict and ambiguity with STAR stories
This question evaluates a candidate's conflict-resolution, cross-functional communication, technical troubleshooting, ambiguity-management, and reflective learning competencies within a data engineering context.
Behavioral & LeadershipTechnical Screen - Capital OneMediumData EngineerDeep-dive XGBoost handling and overfitting
This question evaluates proficiency with gradient-boosted decision trees and related competencies such as native versus imputation handling of missing values, causes and control of overfitting via regularization and hyperparameters, selection of metrics and validation strategies for imbalanced outcomes, and practical debugging concerns like data leakage, time-based splits, and calibration for a Data Engineer role. It is commonly asked in Machine Learning interviews to assess both conceptual understanding of algorithm behavior and practical application of model evaluation and deployment-ready validation techniques.
Machine LearningTechnical Screen - Capital OneMediumData EngineerEvaluate credit-limit increase profitability
This question evaluates a data engineer's competency in business analytics, unit-economics P&L modeling, risk-versus-revenue trade-off analysis, and experiment-driven evaluation of credit product changes.
System DesignTechnical Screen
Agoda
Airbnb
Akuna Capital
Amazon
Apple
Baseten
Bloomberg
Capital One