Built forData Career Growth
Everything you need to master data skills, ace interviews, and land your dream role at top tech companies.
Our Mission
To be the most complete platform for data career growth — covering the skills, questions, projects, and learning paths that take you from curious beginner to confident professional.
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Interview Questions
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Companies Covered
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Members Worldwide
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Data Projects
Built by Data Scientists for Data Professionals
StrataScratch started in 2017 as a small side project from founder Nathan Rosidi, who was not only a working data scientist but also a professor — teaching the next generation of data professionals while seeing firsthand how disconnected most interview prep resources were from the job itself. Most taught generic coding puzzles, not the real, messy, business-driven SQL and Python questions actually asked in data interviews.
Nathan didn't build it alone. Sergey Parkhomenko — a developer by training who had already worked alongside Nathan on a previous startup — joined from the beginning days to turn the idea into a real platform, building the systems that let candidates practice with real questions, sourced from actual interview loops at companies like Amazon, Meta, and Google, and write and run code directly in the browser.
What began as a tool for a handful of early users has grown into a platform trusted by data professionals worldwide, expanding from coding questions into full learning paths, data projects, and career tools. Nathan continues to build the platform according to the vision and needs of data professionals in an ever-changing industry, with Sergey serving as CTO, building StrataScratch with modern tooling and infrastructure. Both are supported by a team of experienced data professionals — data scientists, AI engineers, ML engineers, and data engineers — who help keep StrataScratch true to its mission: preparing people for what's real in the industry, not just what's easy to test.
2017
Founded
2
Co-Founders
San Francisco, CA
Headquarters
“I've watched candidates ace generic puzzles, then freeze on a real interview question or a messy, business-driven data project — because that's not what they'd practiced with. We built StrataScratch on real questions and real projects, sourced from actual interview loops. AI has only raised the stakes: it's not enough to get the right answer anymore, you have to be able to defend it.”
Vision
Data Careers, End to End
The Most Complete Platform for Data Career Growth
We believe preparing for a data career shouldn't mean piecing together scattered SQL tutorials, outdated courses, and disconnected practice problems. It should be one place that grows with you — from your first SELECT statement, to the interview that gets you hired, to the ongoing projects that keep your skills sharp in an ever-changing industry.
That's the vision behind StrataScratch: a single platform that covers the skills, the real questions, the projects, and the learning paths that take someone from curious beginner to confident, hired professional.
Real questions, not guesswork — every question is grounded in what companies actually ask.
One platform, every stage — from foundational learning paths to advanced portfolio projects.
Built with the community — shaped by feedback from the 500K+ members who use it.
Always current — content updated as companies, tools, and interview formats evolve.
What We Stand For
These are the principles that guide what we build and how we support the people using StrataScratch.
Learner-First
Every feature starts with a simple question: does this actually help someone get better or get hired? If it doesn’t serve the learner, we don’t build it.
Real-World Relevance
We source questions and projects from real interviews and real take-home assignments, so practice here actually reflects what happens in the room.
Continuous Innovation
From AI-powered code validation to new project formats, we keep pushing the platform forward as the data field and interview process evolve.
Community-Driven
Our 500K+ members shape the platform through feedback, discussion, and shared solutions — learning together, not alone.
Ahead of an AI-Driven Industry
AI is reshaping interviews and day-to-day data work, so we’re continually updating our questions, practice methods, and tools to match. We’re also building AI into our own toolkit — giving users real-time feedback and adjustments that mirror both the modern interview and daily life as a data professional.
Companies We Follow
We track the data roles, hiring trends, and technical standards at the world’s top companies — so our content always reflects what the industry actually demands.
Technology
Social Media & Entertainment
Fintech & Financial Services
E-Commerce & Marketplace
Real Estate & Local
Healthcare & Wellness
Business Intelligence & Data
Consulting & Professional Services
Travel & Transportation
Cloud & Infrastructure
Job Positions We Follow
We track the specific roles top companies hire for — mapping each position to the skills, question types, and difficulty levels that show up in real interviews.
Data Analyst
Easy – MediumCore skills tested
SQL (aggregations, joins, filtering), Python or R, data visualization, business acumen, product sense
Question types
Reporting queries, metric calculations, cohort analysis, funnel analysis, A/B test interpretation
Top companies
Data Scientist
Medium – HardCore skills tested
SQL, Python (Pandas, NumPy, Scikit-learn), statistics, probability, A/B testing, ML fundamentals, product sense
Question types
Statistical inference, experiment design, predictive modeling, feature engineering, business case studies
Top companies
Machine Learning Engineer
Medium – HardCore skills tested
SQL (window functions, joins, deduplication, cohorts), Python, PySpark, dataset construction, label creation, leakage prevention
Question types
Dataset construction for model training, time-aware feature engineering, churn/fraud/conversion label building
Top companies
Analytics Engineer
Medium – HardCore skills tested
Advanced SQL, data modeling, dbt, dimensional modeling, data warehousing concepts, Python basics
Question types
Data transformation logic, schema design, slowly changing dimensions, pipeline debugging, metric layer design
Top companies
Data Engineer
Medium – HardCore skills tested
SQL, Python, distributed computing (PySpark), ETL design, data modeling, database internals, cloud infrastructure
Question types
Pipeline design, batch/streaming trade-offs, schema migrations, performance optimization, distributed system design
Top companies
BI Analyst
Easy – MediumCore skills tested
SQL, data visualization (Tableau, Looker, Power BI), business metrics, KPI definition, stakeholder communication
Question types
Reporting queries, KPI calculations, trend analysis, cohort comparisons, dashboard logic
Top companies
Product Analyst
MediumCore skills tested
SQL, A/B testing, funnel analysis, retention analysis, product sense, metric definition, experiment design
Question types
Retention queries, funnel drop-off analysis, feature usage metrics, experiment result interpretation, product case studies
Top companies
Skill Sets We Cover
Every skill set on StrataScratch is mapped to real interview requirements. We cover the languages, frameworks, and concepts that top data companies actually test.
SQL
From basic SELECT statements to advanced window functions, CTEs, and multi-table joins. The #1 skill tested in data interviews.
Python
Data manipulation, analysis, and ML workflows. Covers Pandas, NumPy, Scikit-learn, and PySpark for big data environments.
Statistics & Probability
Hypothesis testing, distributions, confidence intervals, p-values, and Bayesian reasoning — core to data science interviews.
Machine Learning
Supervised and unsupervised learning, model evaluation, feature engineering, dataset construction, and deployment concepts.
Product & Business Sense
How to define metrics, analyze product features, interpret business cases, and communicate data findings to stakeholders.
System & Data Design
Data pipeline architecture, schema design, ETL patterns, data warehouse modeling, and system design for data-heavy applications.
Our Content Catalog
A comprehensive set of question types, projects, and concepts — all organized to reflect real-world job requirements across 57+ companies.
1,000+
Coding Questions
Real SQL and Python interview questions from Amazon (68), Meta (62), Google (49), Airbnb (31), and 50+ other companies. Write, run, and validate solutions in our interactive editor.
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Non-Coding Concept Questions
Prepare for the full interview loop with conceptual questions covering statistics, probability, modeling, system design, product sense, business cases, and behavioral rounds.
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Data Projects
Real take-home assignments from top companies. Build in cloud-hosted Python notebooks — no setup required. Projects cover ML, NLP, forecasting, and analytics. Share your work directly from your performance page.
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Algorithm Questions
Sharpen your algorithmic thinking with questions covering sorting, searching, dynamic programming, graph traversal, and optimization — the kind asked at top-tier tech companies.
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Visualization Questions
Practice creating charts, dashboards, and visual analyses. Build fluency with Matplotlib, Plotly, and Folium through hands-on exercises that mirror real BI and analytics interviews.
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Free Questions
Start practicing without a subscription. 62 real interview questions — spanning easy through medium difficulty — available to all users with no credit card required.
Career Paths
Whether you’re breaking into data, leveling up, or pivoting to a new specialization — StrataScratch maps a path for every stage of the data career journey.
Breaking Into Data
Build foundational SQL and Python skills through structured learning paths. Practice easy-to-medium questions from real companies and work toward your first data role.
Leveling Up Your Skills
Advance from analyst to scientist or engineer. Tackle medium-to-hard problems, work on real data projects, and build a portfolio that gets you noticed by top companies.
Targeting Senior Roles
Prepare for hard-difficulty interview rounds, system design questions, and advanced ML topics. Practice the exact challenges asked at FAANG and top-tier companies.
Pivoting Into Data
Coming from software engineering, finance, or another field? Use our company-specific question sets and concept guides to bridge the gap into data roles quickly.
Deepening a Specialization
Go deep on a specific domain — machine learning, data engineering, or product analytics. Our curated question sets and data projects let you master the skills that matter most.
AI & ML Career Path
One of the hottest paths in tech. StrataScratch covers the SQL data foundations, Python ML workflows, and dataset-building skills that AI engineers need to pass interviews.
Learning Paths, Questions & Data Projects
Progressive skill-building from free foundational learning paths to company-specific interview questions and cloud-hosted data projects.
Comprehensive SQL
FreeMaster SQL from foundations to advanced window functions. Covers everything needed for data analyst and data scientist interviews at top companies.
- SQL Foundations — SELECT, WHERE, ORDER BY
- Aggregating & Grouping — GROUP BY, HAVING
- Working with Multiple Tables — JOINs, UNION
- Subqueries & CTEs
- Date, Time & Text Functions
- Window Functions — ROW_NUMBER, LAG, LEAD
Comprehensive Python
FreeLearn Python for data analysis from the ground up. Covers Pandas, NumPy, data cleaning, and analytical workflows used in real data science roles.
- Python Fundamentals & Data Types
- Pandas — DataFrames, filtering, groupby
- NumPy — Arrays and numerical computing
- Data Cleaning & Transformation
- Exploratory Data Analysis
- Applied Python for interviews
Company-Specific Interview Prep
ProFilter questions by company, difficulty, and programming language. Practice the exact questions asked at Amazon, Meta, Google, Airbnb, and more.
- Amazon — 68 questions across all difficulties
- Meta — 62 questions, heavy on window functions
- Google — 49 questions, advanced SQL & Python
- Airbnb — 31 questions, product analytics focus
- ESPN, City of SF, Uber, Spotify & more
Data Projects (Data Labs)
ProPractice real take-home assignments in cloud-hosted Python notebooks. Build a portfolio, share your work publicly, and demonstrate skills to recruiters.
- Delivery Duration Prediction (DoorDash)
- Customer Churn Prediction (Sony Research)
- Driver Lifetime Value (Lyft)
- Fraudster Detection (Revolut)
- Stock Price Direction Prediction
- Response to Marketing Campaign
Assessments & Performance
Track your growth, benchmark against 500K+ members, and build a public data profile that gets you noticed by recruiters.
Progress Tracking
Track every question you solve across SQL, Python, and analytics. See your improvement over time with detailed skill-level breakdowns by topic and difficulty.
Community Rankings
See how you stack up against 500K+ members worldwide. Rankings are broken down by skill area so you can see exactly where you stand relative to your peers.
Public Data Profile
Coming soonBuild a public profile showcasing your solved questions, data projects, and skill benchmarks. Share it directly with recruiters as proof of your abilities.
Portfolio Integration
Coming soonLink your GitHub repos to your StrataScratch profile. Combine completed data projects and real interview questions into a single shareable portfolio page.
Skill Benchmarking
Understand exactly which skills you need to improve before your interview. Our platform identifies your weak spots across SQL, Python, statistics, and conceptual topics.
Scorers and Evaluators
Coming soonAI-driven scorers evaluate both the quantitative correctness and qualitative reasoning behind your solutions — mimicking real interviews where you have to explain and defend your logic, not just submit a working answer, across questions and data projects alike.
How to Use StrataScratch
A simple, personalized path from your goals to your dream data role. Start with an intake form, follow your learning path, and level up through practice and assessment.
Complete the intake form
Tell us your goals, background, and target role. We’ll match you to the right persona — Learner, Interview Prep, or Project Pro — based on where you are.
Start your learning path
Begin with free SQL or Python learning paths for foundational skills, or jump straight into company-specific interview questions if you’re actively job hunting.
Practice with real questions
Work through 1,000+ real interview questions from Amazon, Meta, Google, and 50+ other companies. Write and run code directly in our interactive editor.
Build your portfolio
Take on cloud-hosted data projects modeled after real company take-home assignments. Share completed projects publicly from your performance page.
Track & benchmark progress
See your rankings against 500K+ members, identify skill gaps, and use our AI-driven Scorers and Evaluators to validate and defend your solutions before the real interview.
Our Three Personas
StrataScratch is built around three modes — each tailored to where you are in your data journey. Take the intake form to find yours.
Building Foundations
Start free and learn core data skills at your own pace through structured, beginner-friendly learning paths in SQL and Python.
- Free Comprehensive SQL path — 6 modules, 36 lessons
- Free Comprehensive Python path — Pandas, NumPy, analysis
- 62 free interview questions, no credit card required
- Progress tracking and community benchmarking
Get Hired
Targeted, company-specific practice designed to get you through the technical interview and land the role at top data companies.
- 1,000+ real questions from Google, Meta, Amazon & more
- Filter by company, difficulty, and programming language
- Non-coding concept rounds — stats, probability, product sense
- AI-driven Scorers and Evaluators to validate and defend your solutionsComing soon
Sharpen the Edge
Advanced challenges and hands-on data projects for experienced practitioners who want to stay sharp, go deeper, and build a public portfolio.
- Hard-difficulty coding challenges across all languages
- 51+ cloud-hosted data project notebooks
- Real take-home assignments from DoorDash, Lyft, Revolut & more
- Public data profile and GitHub portfolio integrationComing soon
What Our Members Say
Join 500,000+ data professionals who have used StrataScratch to land jobs at top tech companies.
“StrataScratch is hands down the best platform if you are preparing for or am working as a data analyst/scientist/engineer. Happy to share that I have gotten an offer from Amazon as a Data Analyst.”
Triman
Data Analyst @ Amazon
“StrataScratch has been super helpful. I started with barely being able to finish an easy SQL query to no problem solving most of the medium level in just a few days.”
Kyle
@ Twitch
“StrataScratch and the community really helped me prep for the interview — I ended up getting the Data Scientist internship!”
Joe
Data Scientist @ Microsoft
“I really wanted to get into data analytics and data science but never really understood the importance of SQL. The questions are really very realistic and I was asked similar questions in my coding rounds.”
Hemant R.
@ Credit Karma
“SQL is something that is super important and plays a key role in Data Analysis. I used to practice 2–3 SQL problems everyday. The discussion forum and solution with clear understanding cleared my barriers.”
Vikram
@ Microsoft
“StrataScratch is awesome! It’s the first place I found that allows you to use Python in addition to SQL. The Facebook questions were quite similar to the ones that I saw in my interview today.”
Ryan
@ Meta
Ready to Land YourDream Data Role?
Start practicing with real interview questions today. No credit card required.