Data-engineering assessment + hands-on learning

Every engineer has blind spots. Find yours in 25 minutes.

Take practical Data Engineering assessments, discover where you need to improve, and build your skills through focused lessons and hands-on practice.

Start free assessment →See sample report →
Free · about 25 minutes · no credit card
How it feels to useExample
You assessedSQL & Querying · 25 minRealistic tasks, graded against a senior-engineer rubric.
Readineer foundA gap in filtering & predicatesYour query kept a row it shouldn’t. The finding shows the line and why.
You practise nextP01 · Filtering rows & conditions13 problems, in your browser. Then reassess, dated.
See a full report, finding by findingOpen →
How it works

A simple way to understand and improve your skills.

  1. 1Assess your skills

    Solve realistic problems that test how you write code, debug, and reason about systems.

    ~25 minSQL · free

  2. 2Understand your results

    A report shows what you did well, where you struggled, and which skills to improve first.

    Priority 1Gap found · linked to your work

  3. 3Learn and practise

    Follow targeted lessons, run practice problems in the browser, and ask Colearn when you need guidance.

    P01 · 13problems on your first gap
What you get

See what went wrong and how to fix it.

Here’s one finding. A learner submits a data pipeline that writes results, but running it again could create duplicate records. Readineer identifies the problem, explains why it matters, and shows what to learn next.

The submitted solution
def publish_results(rows, sink):
for row in rows:
sink.append(row)
mark_done()
If the task fails after writing and runs again, line 3 appends the same rows a second time.
What Readineer findsYour pipeline can write duplicate records when a task is retried.
Why it matters

A failed attempt may already have written its output. Running the write again doubles those rows, and the totals built on them come out high. Nothing errors, so nobody notices.

What to learn nextF04.2When a task writes the same data twice43 minThen practise safe retries until a rerun leaves the same result.
Explore the full sample report →
Illustrative. The finding comes from F04’s live lesson and lab.
Why it helps

Spend less time guessing. More time improving.

Know where you need to improve

See which skills are strong and which need work, based on what you actually wrote, not a quiz score.

Report“4 priority gaps · 1 demonstrated · 13 not assessed”

Practise real engineering problems

Work on failures that happen in production: wrong totals, duplicate writes, slow jobs, late data.

+9.6%a retried write counted revenue twice

Understand the reasoning

Learn why a solution works, why another fails, and which trade-offs matter.

F04.2why a retry duplicates, and which sinks prevent it

Follow a focused path

Spend your study time on the gaps that matter most, instead of studying at random.

Nextyour first gap, then reassess, dated
Skills covered

Six areas of real data-engineering work.

Browse the lessons →
  • SQL

    SQL & Querying

    Write queries whose results are right, not just runnable.

    Learn + practice · 24 lessons · 320 problems
  • Python · pandas

    Programming for Data

    Load, clean and validate data before any engine sees it.

    Coming soon
  • Spark · Kafka · Flink

    Distributed Data Processing

    Understand how engines share, move and recover work.

    Coming soon
  • Airflow

    Pipeline Orchestration & Reliability

    Build pipelines that recover safely from failures.

    Coming soon
  • dbt · Iceberg · Snowflake · Redshift

    Data Modeling & Storage Design

    Choose the grain and layout that make numbers agree.

    Coming soon
  • System design

    System & Scenario Judgment

    Architecture decisions and trade-offs.

    Coming soon
Learning and Colearn

Learn step by step, with Colearn to guide you.

Structured learning

Each gap points to a lesson named for its trap, then to practice problems that run in your browser. Lessons move from the concept to realistic failures to the judgment calls behind them.

  1. 1Read the lesson that names your trapconcept
  2. 2Run the problems where it bitesin browser
  3. 3Reassess, and the report updatesdated

Colearn, when you’re stuck

Your personal learning companion, with answers grounded in Readineer’s learning material and the lesson or challenge you’re working on. On a practice challenge, it coaches you through the steps instead of handing over the answer.

ColearnThis lesson
You“Why can this pipeline create duplicates after a retry?”
ColearnThe earlier attempt may have written records before failing. If the next attempt writes the same records again, the output can contain duplicates. Look at your sink: what happens when the same row arrives twice?
You“It appends. So I need a write that overwrites by key?”
Illustrative conversation. Colearn is grounded in Readineer’s material and can decline off-topic questions.See how Colearn works →
Get started

Find out where you stand. Start improving today.

Take an assessment, see your gaps, and know where to focus your learning.

Start free assessment →Explore sample report →

Baseline

₹0

Pick a skill area and see where you actually stand.

Practice Pass

₹2,199

See the whole picture, then practise your gaps in the tools you’ll actually be tested on.

Coached Pass

₹5,999

Every tool, your personal learning companion, and the bar itself.

Full pricing details →

About 25 minutes for SQL.