LeetCode and HackerRank alternative
LeetCode and HackerRank are where most people practice for coding interviews, and they are good at it. A data engineering interview loop asks for more: SQL on messy warehouse tables, PySpark transforms, data modeling, and questions about Airflow, dbt, and Kafka. Lakebench is built for those rounds. Every problem runs in your browser, with no database or Spark cluster to set up.
Algorithms and data structures. Arrays, trees, graphs, and dynamic programming, with huge problem banks and active discussion. If your target company runs a classic DSA round, keep using them for it. Their SQL sections exist, but they are a small side of the product, usually on small toy tables.
Writing SQL at the right grain after a join, window functions over event data, deduplicating late or repeated records, and explaining why a query is slow. Transforming DataFrames in PySpark or Pandas. Modeling a star schema or a slowly changing dimension. Talking through how you would build, schedule, and monitor a pipeline. These are the rounds that decide most data engineering offers.
60 SQL problems on a shared set of warehouse tables, 120 Python and DSA problems framed around data work, and 65 PySpark and Pandas problems. SQL runs on DuckDB and Python on Pyodide, both inside the browser tab. Around them: 11 learning tracks with 180 lessons, 445 interview theory questions with full answers, timed mock interviews, and a 45-day study plan.
Use LeetCode or HackerRank for the pure algorithms round. Use Lakebench for SQL, PySpark, modeling, and pipeline questions, and for practicing how to explain your answer out loud. Most candidates are weakest on the second list, because general coding sites cover it the least.
Runnable tickets on warehouse tables in your browser.
Free Lakebench SQL drill. Filter Engineering salaries on the shared studio tables.
Free Lakebench Python drill. Flatten nested lists without splitting strings.
Free Lakebench PySpark drill. Cast string CSV columns to an explicit schema.
Not sure where to begin?
Answer two questions and we'll point you at one first lesson and one free practice ticket.