Data Engineer career guide
Build the pipelines and platforms that get reliable data to everyone who needs it.
What does a data engineer do?
A data engineer designs and runs the systems that move data from where it is created into warehouses and lakes where it can be analysed. Analysts and data scientists depend on this work.
The role is closer to software engineering than analysis: writing production code, designing schemas, and making pipelines reliable, fast and cost-effective.
Typical responsibilities
- Build and maintain batch and streaming data pipelines
- Design data models for warehouses and lakes
- Ensure data quality, testing and monitoring
- Optimise queries and pipeline cost and performance
- Manage access, security and governance of data
- Work with analysts and data scientists on what data they need
Skills you need
Technical skills
- Advanced SQL and query optimisation
- Python for data processing
- Data modelling (star schema, dimensional modelling)
- ETL/ELT pipeline design
- Distributed processing with Apache Spark
- Cloud data services on AWS, Azure or Google Cloud
- Orchestration (for example Apache Airflow)
Soft skills
- Designing for reliability
- Clear technical documentation
- Working with data consumers
- Debugging methodically
Tools and technologies
- SQL
- Python
- Apache Spark
- Apache Airflow
- dbt
- Apache Kafka
- Snowflake
- Databricks
- AWS, Azure or Google Cloud data services
Certifications
- AWS Certified Data Engineer – AssociateIntermediateAWS
- Microsoft Certified: Fabric Data Engineer Associate (DP-700)IntermediateMicrosoft · Replaced the retired DP-203
- Google Cloud Professional Data EngineerAdvancedGoogle Cloud
- Databricks Certified Data Engineer AssociateIntermediateDatabricks
Certifications are optional for most roles; skills and projects matter more. Providers retire and rename exams regularly, so check the provider's website before you register. Last reviewed October 2026.
Data Engineer salary
Career path
- Step 1Associate Data Engineer
- Step 2Data Engineer
- Step 3Senior Data Engineer
- Step 4Lead Data Engineer
- Step 5Data Engineering Manager or Data Architect
Titles and the time between steps vary by company and individual.
Your first 90 days of learning
SQL, Python and data modelling
- Master joins, window functions and query plans in SQL
- Write Python scripts that read, transform and load files
- Design a star schema for a sample sales dataset
Pipelines and processing
- Build a scheduled ETL pipeline with Airflow
- Process a large dataset with Spark
- Learn one cloud provider's storage and warehouse services
Production habits and portfolio
- Add data-quality tests and monitoring to your pipeline
- Document the architecture of one end-to-end project
- Practise explaining trade-offs: batch vs streaming, ETL vs ELT
Interview preparation
Common topics to prepare for data engineer interviews. These are preparation areas, not questions from a specific company's interview.
- Advanced SQL and query optimisation
- Data modelling: facts, dimensions and slowly changing dimensions
- Designing an ETL pipeline end to end
- Batch vs streaming processing
- Spark fundamentals: partitions and shuffles
- Ensuring data quality and handling late data
Resume guidance
- Describe the scale and reliability of systems you built, accurately
- Name the stack for each project: sources, processing, storage, orchestration
- Show ownership: what you designed vs what you maintained
- Link a repository with a documented pipeline project
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