IBM
Global technology and consulting firm with deep roots in enterprise IT and AI.
3 Rounds
~14 Days
Medium
The Interview Loop
Recruiter Screen (30 min)
Standard fit check, behavioral questions, and resume overview.
Technical Loop (3-4 Rounds)
Deep dive into domain knowledge, coding, and system design.
Interview Question Bank
Data Engineer
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Behavioral
•
easy
How do you prioritize tasks when you have multiple urgent deadlines?
#Time Management
#Agile
Data Engineer
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Behavioral
•
easy
Why do you want to work as a Data Engineer at IBM?
#Motivation
#Company Knowledge
Data Engineer
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Behavioral
•
medium
Describe a time you optimized a slow-running process. What was the impact?
#Performance Tuning
#Impact
Data Engineer
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Behavioral
•
medium
Tell me about a time you disagreed with a senior engineer or manager on an architectural decision.
#Conflict Resolution
#Communication
#Leadership
Data Engineer
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Behavioral
•
medium
Describe a situation where you had to work with incomplete or dirty data. How did you handle it?
#Problem Solving
#Data Quality
Data Engineer
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Behavioral
•
medium
Tell me about a time you missed a project deadline. What happened and what did you learn?
#Accountability
#Time Management
Data Engineer
•
Behavioral
•
medium
Tell me about a time you had to explain a complex data engineering concept to a non-technical stakeholder.
#Communication
#Stakeholder Management
Data Engineer
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Coding
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medium
Write a SQL query to find the top 3 highest paid employees in each department.
#Window Functions
#DENSE_RANK
#PARTITION BY
Data Engineer
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Coding
•
medium
Write a SQL query to calculate a 7-day rolling average of daily sales.
#Window Functions
#Moving Average
#Date Functions
Data Engineer
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Coding
•
medium
How would you delete duplicate rows from a massive table in DB2 or PostgreSQL without creating a new table?
#Data Cleaning
#CTID
#ROW_NUMBER
Data Engineer
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Coding
•
easy
Write a Python function to find the first non-repeating character in a string.
#Strings
#Hash Maps
Data Engineer
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Coding
•
medium
Write a Python script to merge multiple large CSV files efficiently without loading them entirely into memory.
#File I/O
#Generators
#Memory Management
Data Engineer
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Coding
•
medium
Parse a JSON log file in Python and extract specific error codes, returning a count of each error type.
#JSON
#Data Parsing
#Dictionaries
Data Engineer
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Coding
•
medium
Write a SQL query to find the cumulative sum of sales by month.
#Window Functions
#Cumulative Sum
Data Engineer
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Coding
•
medium
Write a Python script using Pandas to join two large datasets and handle missing values in the resulting dataframe.
#Python
#Pandas
#Data Cleaning
Data Engineer
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System Design
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hard
Design a batch pipeline to ingest 10TB of daily log data into a data lake on IBM Cloud.
#Batch Processing
#Data Lake
#IBM Cloud Object Storage
#Spark
Data Engineer
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System Design
•
hard
Design a real-time streaming pipeline for credit card transaction fraud detection.
#Streaming
#Kafka
#Spark Streaming / Flink
#Low Latency
Data Engineer
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System Design
•
hard
How would you migrate an on-premise DB2 database to a cloud data warehouse with minimal downtime?
#Cloud Migration
#CDC
#DB2
Data Engineer
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System Design
•
medium
Design an idempotent data pipeline. Why is idempotency important?
#Idempotency
#Data Pipelines
#Fault Tolerance
Data Engineer
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System Design
•
medium
Design a data model for a retail e-commerce platform.
#Data Modeling
#Fact Tables
#Dimension Tables
Data Engineer
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System Design
•
hard
Design a metric aggregation system that handles late-arriving events in a streaming architecture.
#Streaming
#Watermarking
#Event Time vs Processing Time
Data Engineer
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Technical
•
medium
Explain how Apache Spark handles fault tolerance.
#Spark
#RDD Lineage
#DAG
Data Engineer
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Technical
•
hard
How do you resolve an OutOfMemory (OOM) error in a Spark application?
#Spark
#Performance Tuning
#Memory Management
Data Engineer
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Technical
•
medium
Explain the difference between repartition() and coalesce() in Spark. When would you use each?
#Spark
#Data Shuffling
#Optimization
Data Engineer
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Technical
•
hard
What is data skew in Spark, and how do you mitigate it?
#Spark
#Data Skew
#Salting
Data Engineer
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Technical
•
medium
Explain the concept of Broadcast Variables and Accumulators in Spark.
#Spark
#Shared Variables
Data Engineer
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Technical
•
easy
Explain the difference between a Star Schema and a Snowflake Schema.
#Data Warehousing
#Dimensional Modeling
Data Engineer
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Technical
•
medium
How do you implement a Slowly Changing Dimension (SCD) Type 2?
#Data Warehousing
#SCD
#ETL
Data Engineer
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Technical
•
easy
Explain the difference between ETL and ELT. When would you choose ELT over ETL?
#ETL
#ELT
#Cloud Data Warehouses
Data Engineer
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Technical
•
medium
How do you handle task dependencies and retries in Apache Airflow?
#Airflow
#DAGs
#Error Handling
Data Engineer
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Technical
•
medium
Explain how Apache Kafka guarantees message ordering.
#Kafka
#Partitions
#Message Queues
Data Engineer
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Technical
•
easy
What is the difference between RANK(), DENSE_RANK(), and ROW_NUMBER() in SQL?
#Window Functions
#Ranking
Data Engineer
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Technical
•
hard
What is the Catalyst Optimizer in Spark SQL?
#Spark
#Internals
#Optimization
Data Engineer
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Technical
•
easy
Explain the difference between object storage (e.g., IBM Cloud Object Storage/S3) and block storage.
#Storage
#Cloud Architecture
Data Engineer
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Technical
•
medium
What are Parquet and ORC formats? Why are they preferred in Big Data over CSV or JSON?
#File Formats
#Storage Optimization
Difficulty Radar
Based on recent AI-sourced data.
Meet Your Interviewers
The "Standard" Interviewer
Senior EngineerFocuses on core competencies, system constraints, and clear communication.
SimulateUnwritten Rules
Think Out Loud
Always explain your thought process before writing code or drawing architecture.