What is Data Engineering?

Data Engineering is the practice of designing, building and maintaining the systems that collect, store, transform and serve data reliably at scale. Data engineers build data pipelines (ETL/ELT), model data warehouses and lakehouses, and make clean, trustworthy data available to analysts, data scientists and applications.

Core skills

SQL and Python are foundational; then distributed processing (Apache Spark / PySpark), workflow orchestration (Airflow, Dagster), streaming (Kafka), warehouses (Snowflake, BigQuery, Databricks), and cloud (AWS/GCP/Azure).

What data engineers build

Batch and streaming pipelines, medallion (bronze/silver/gold) layers, data models, data-quality checks, and the infrastructure that powers analytics and machine learning.

Example (SQL)

-- A tiny slice of a data engineer's job: aggregate raw events into a daily table
SELECT
  event_date,
  COUNT(*)                    AS events,
  COUNT(DISTINCT user_id)     AS active_users
FROM bronze_events
GROUP BY event_date
ORDER BY event_date;

Transforming raw event data into a clean daily metrics table is a typical Data Engineering task.

Run this example in the free online PySpark compiler

Frequently asked questions

What does a data engineer do?

A data engineer designs and maintains the pipelines and storage that collect, transform and serve data — turning raw data into clean, reliable datasets for analytics and ML.

What skills do you need for Data Engineering?

SQL, Python, distributed processing (Spark/PySpark), orchestration (Airflow), streaming (Kafka), data warehouses (Snowflake/BigQuery/Databricks) and cloud platforms.

What is the difference between a data engineer and a data scientist?

Data engineers build and maintain the data infrastructure and pipelines; data scientists use that clean data to build models and generate insights.

How do I practice Data Engineering for free?

Use PySpark.in — run PySpark and SQL in the browser and solve auto-graded Data Engineering challenges, no setup required.

Open the free PySpark compiler · Data Engineering challenges · Data Engineering jobs