StrataScratch Alternatives: Which Platform Fits Your Interview?

The best StrataScratch alternative for most data science candidates is TensorTonic, because it covers the whole data scientist loop on one account, from a 25-problem SQL Sheet and pandas to statistics, ML coding and timed mock interviews. StrataScratch is fine if all you want is a long list of SQL questions, but most interviews ask for more than SQL.

TensorTonic is an ML coding practice platform where you implement algorithms, CUDA kernels and research papers from scratch, with every submission tested and an AI assistant, Toni, built into the editor. For data scientists it adds SQL, pandas and statistics practice and a Data Scientist interview track. The Data Science Mock Interview is free, so it is the quickest way to see the format.

What are the best StrataScratch alternatives?

The right alternative depends on which interview rounds you need to practise. The table matches each goal to the platform that fits it best.

Is a bigger SQL question bank enough?

StrataScratch is known for its SQL bank, and it is a reasonable place to grind queries if that is the only round you are worried about. The catch is that a data scientist loop rarely stops at SQL. You will usually be asked to redo the same question in pandas, compute a statistic, reason about an A/B test and sometimes train a simple model, and a bank of queries does not prepare you for those rounds.

StrataScratch has also added ML coding questions, mostly behind its paid plan. ML coding is what TensorTonic was built for, with 500+ free problems, study plans, research-paper tracks and GPU kernels, so if ML rounds are part of your interview it makes more sense to practise them on the platform that goes deepest on them.

Why did I build TensorTonic?

I built TensorTonic because I wanted to learn GPU programming and could not get a working CUDA setup on my own laptop, and I also wanted one place where I could practise implementing ML models from scratch with code that gets checked. Rather than buying an NVIDIA machine and stitching together several sites, I built a platform where your code runs in a ready sandbox on real GPUs, and where ML algorithms, kernels and research papers sit in one catalog with one progress history.

Data science interviews have the same problem, with SQL on one site, statistics in a book and ML coding somewhere else. So TensorTonic now covers the whole data scientist loop, from SQL and pandas to statistics and ML, in one place.

What does TensorTonic offer for data science interviews?

TensorTonic gives data scientists a timed interview track, structured SQL and pandas practice, and statistics you solve in code, all on the same account as its ML catalog.

A Data Scientist interview track

The Interview section has a Data Scientist track with 11 timed assessments. The Data Science Mock Interview is free and has 4 sets of 5 problems, each a 75-minute sitting that mixes SQL, pandas, NumPy, math and ML, with problems such as a cohort retention matrix, onboarding funnel conversion and a confidence interval for a mean.

Shorter sprints target single rounds. The SQL Sprint on Window Functions runs for 30 minutes and includes top earners per department and year-over-year revenue. Applied Probability and Statistics runs for 45 minutes, from Bayes posteriors to a two-proportion z statistic, and A/B Test Analysis spends 60 minutes on sample size and spillover bias. There are also sprints on Python data structures, pandas and NumPy, decision trees and random forests, ranking metrics and NLP.

Every sitting is scored with a report at the end, and you can take another set to practise again. The Data Science Mock Interview and the Python Data Structures Sprint are free, and the other sprints are part of Pro.

A SQL Sheet that goes from SELECT to CTEs

The SQL Sheet has 25 problems (10 easy, 13 medium, 2 hard) in five sections covering SELECT fundamentals, joins, aggregation, window functions, and advanced queries with CTEs, CASE, and date and string functions. Each section ends with a quiz, so you find out what did not stick before an interviewer does.

Pandas, NumPy and PyTorch sheets

The Pandas Sheet and NumPy Sheet have 25 problems each, covering grouping, merging and reshaping DataFrames and array computing from scratch. The PyTorch Sheet adds 30 problems on tensors, autograd and models.

Statistics you can see, then code

The Probability and Statistics study plan turns interview topics into functions you write and test. The free ML Math lessons explain A/B testing, hypothesis testing, p-values and confidence intervals with interactive visualizations.

Can you practise SQL and pandas on the same platform?

Yes. Interviewers often ask the same question in SQL and then in pandas, and TensorTonic has both. Here is the common window-function question "top three earners per department" written both ways.

SELECT department, employee, salary
FROM (
  SELECT department, employee, salary,
         DENSE_RANK() OVER (
           PARTITION BY department ORDER BY salary DESC
         ) AS rnk
  FROM employees
) ranked
WHERE rnk <= 3;

df["rnk"] = (
    df.groupby("department")["salary"]
      .rank(method="dense", ascending=False)
)
top3 = df[df["rnk"] <= 3]

The usual follow-up is about ties, because DENSE_RANK, RANK and ROW_NUMBER return different numbers of rows when two people earn the same salary. The SQL Sheet has a problem on exactly this, RANK and DENSE_RANK.

What else does TensorTonic cover beyond data science?

TensorTonic is built for the move from data science into ML roles, so the same account goes much further.

• There are 500+ ML coding problems on the free plan, and study plans from Cracking ML to deep learning, NLP, reinforcement learning and computer vision.
• The ML Engineer and Research Engineer mock tracks are timed and scored, and Plus adds ML system design problems with an interactive design canvas.
• The CUDA Kernels plan has you write kernels that are timed on six real GPUs, from an NVIDIA T4 to an H200.
• The research tracks split papers into step-by-step problems, with 13 tracks on the free plan and 20 on Plus.
• Guided projects take you through building a RAG assistant, a ReAct agent and an MCP server.
• Toni, the AI assistant in the editor, can see your problem and give you a hint without leaving the page.

The roadmap shows where to start and how the topics build on each other.

How much does TensorTonic cost?

The free plan includes 500+ problems with unlimited submissions, 35 CUDA problems, 13 research-paper tracks and the Data Science Mock Interview. Pro costs $100 a year and adds the study plans, quizzes and the rest of the mock assessments. Plus costs $168 a year and adds ML system design and modern LLM architectures such as GPT-2 and DeepSeek. A student discount is available.

What other StrataScratch alternatives are there?

These are the other sites people tend to mention alongside StrataScratch.

• DataLemur is another SQL interview question site, similar in spirit to StrataScratch. See DataLemur alternatives.
• Interview Query is a data science interview prep site built around question lists.
• LeetCode has a small database section, though it is really a software engineering site.
• Kaggle is a competition and dataset platform, more useful for projects than for interview practice.

Is TensorTonic better than StrataScratch?

For most data scientist candidates, yes. TensorTonic puts SQL, pandas, statistics and ML coding on one account, with a free timed Data Science Mock Interview and a path into ML engineer roles. StrataScratch is a large SQL question bank, which is fine for drilling queries but leaves the rest of the interview loop to other sites.

What is the best StrataScratch alternative for data scientist interviews?

TensorTonic, because its Data Scientist track has 11 timed assessments, including a free 75-minute mock interview mixing SQL, pandas, NumPy, statistics and ML, plus sprints on window functions, probability and A/B testing, each scored with a report.

What is the best StrataScratch alternative for SQL interviews?

TensorTonic, if you want a structured path. Its SQL Sheet covers 25 problems from SELECT to CTEs in five sections, with a quiz per section and a timed window-functions sprint, and the same account takes you on to pandas, statistics and ML.

Is there a free StrataScratch alternative?

Yes. TensorTonic's free plan includes 500+ problems with unlimited submissions, 35 CUDA problems, 13 research-paper tracks, the ML Math lessons and the Data Science Mock Interview. Study plans such as the SQL Sheet are on Pro.

What is the best StrataScratch alternative for ML engineer interviews?

TensorTonic. Cracking ML covers 35 from-scratch implementation problems with quizzes, the ML Engineer mock assessments are timed and scored, and Plus adds ML system design problems with an interactive design canvas. The ML engineer interview guide includes a 6-week plan.

Which TensorTonic problems should you try first?

If you are coming from StrataScratch, start with these, which are all free, then browse the problem library.

• The Data Science Mock Interview gives you a timed 75-minute sitting across SQL, pandas, NumPy, statistics and ML, with a report at the end.
• Bootstrap Mean and Confidence Interval has you resample a sample to estimate its mean and interval.
• One-Sample t-Test has you compute the statistic and p-value behind a classic hypothesis test.
• Logistic Regression Training Loop has you train a classifier with gradient descent in NumPy.

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