Interview Prep

Senior data engineering interview preparation — SQL, Spark, streaming, GCP, modeling, system design, and behavioral rounds, with practice questions you can self-test on.

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SQL & Coding0/2 · 0%
Spark & Distributed Processing0/2 · 0%
Streaming & Real-Time0/2 · 0%
GCP & Cloud0/2 · 0%
Data Modeling & dbt0/2 · 0%
Architecture & System Design0/3 · 0%
Orchestration & DevOps0/2 · 0%
Behavioral & Leadership0/2 · 0%

SQL & Coding

Intermediate12 min read

SQL Interview Patterns You Must Know

The handful of SQL patterns that show up in almost every data engineering interview — window functions, deduplication, gaps and islands, and running totals — each with a worked example.

Intermediate11 min read

Python and PySpark Coding Rounds

What actually gets asked in the coding round for a data engineer — file and JSON handling, idempotent transforms, and the PySpark DataFrame operations you should be able to write without thinking.

Spark & Distributed Processing

Intermediate10 min read

Spark Architecture Explained Simply

Driver, executors, jobs, stages, tasks, and why the shuffle is the thing that decides whether your job takes 4 minutes or 4 hours.

Advanced12 min read

Spark Performance Tuning and Data Skew

The practical playbook for making a slow Spark job fast — spotting skew, choosing the right join strategy, fixing small files, and reading the Spark UI like an engineer, not a tourist.

Streaming & Real-Time

Intermediate12 min read

Kafka Deep Dive for Interviews

Topics, partitions, offsets, consumer groups, and delivery guarantees — explained simply, plus the operational questions interviewers ask about lag, ordering, and rebalances.

Advanced12 min read

Spark Structured Streaming and Exactly-Once

Micro-batches, checkpointing, watermarks, and late data — the concepts behind cutting a pipeline from hours to minutes, and how to explain that work in an interview.

GCP & Cloud

Advanced13 min read

BigQuery Deep Dive: Performance and Cost

How BigQuery actually runs a query, why partitioning and clustering matter more than anything else, and how to answer the cost-optimisation questions that always come up.

Intermediate11 min read

GCP Data Services: Choosing the Right Tool

Dataflow vs Dataproc vs BigQuery, Pub/Sub, Cloud Composer, GCS, and the architecture questions a Google Certified Professional Data Engineer is expected to answer instantly.

Data Modeling & dbt

Advanced13 min read

Dimensional Modeling Interview Questions

Grain, facts, dimensions, and slowly changing dimensions — the modeling questions that decide whether you are hired as a senior engineer, with worked telecom examples.

Intermediate12 min read

dbt and the Transformation Layer

How dbt structures a warehouse, incremental models, tests, snapshots, and the layered Raw → Stage → Core architecture — plus the questions asked about maintaining it at enterprise scale.

Architecture & System Design

Advanced14 min read

How to Answer Data Pipeline System Design

A repeatable framework for the design round — clarify, size, sketch, then defend your trade-offs — with a full worked example you can adapt to almost any prompt.

Advanced14 min read

Hadoop to Cloud Migration: The Full Story

How to plan, sequence and defend a large on-prem Hadoop to GCP migration — service mapping, migration patterns, validation strategy, and the questions asked about risk and rollback.

Advanced11 min read

Data Quality, Reliability and Observability

How to make a platform trustworthy — the layers of testing, data contracts, SLAs, incident response, and how to answer 'how do you know your data is correct?'

Orchestration & DevOps

Intermediate11 min read

Orchestration: Airflow, Composer and Dagster

Scheduling concepts that trip people up, the task-centric vs asset-centric difference between Airflow and Dagster, and how to answer questions about retries, backfills and SLAs.

Intermediate10 min read

CI/CD, Docker and Kubernetes for Data Engineers

The platform-engineering side of the role — testing data pipelines in CI, environment strategy, containerisation, secrets, and infrastructure as code.

Behavioral & Leadership

Intermediate11 min read

Behavioral and Leadership Questions

The STAR method applied to senior data engineering — prepared stories for conflict, failure, mentoring, influence without authority, and stakeholder pushback.

Advanced12 min read

Defending Your Resume: The Deep-Dive Round

Interviewers will pick the biggest claims on your CV and push until they find the edge of your knowledge. Here is how to prepare each headline achievement so the depth is genuinely there.