Technical interviews
Explain domain methods, work through examples and test edge cases.
Speak or type. Every round ends with feedback linked to your own words.
Practice tracks
Machine learning theory and cases
Explain generalization, leakage, metrics, calibration and model interpretation with supplied evidence.
6 scenarios
Machine learning theory and cases
Explain generalization, leakage, metrics, calibration and model interpretation with supplied evidence.
- A demand model with a wide validation gap35 min · 4 stagesStart
- A fraud metric under review capacity35 min · 4 stagesStart
- A churn model that looks too good35 min · 4 stagesStart
- Cross-validation for repeated clinic visits35 min · 4 stagesStart
- A ranked risk score with unreliable probabilities35 min · 4 stagesStart
- A leading feature and an unsupported causal claim35 min · 4 stagesStart
SQL live interview
Write and run a query. Explain its grain, test awkward rows and read the result.
10 scenarios
SQL live interview
Write and run a query. Explain its grain, test awkward rows and read the result.
- Accounts with and without activity25 min · 4 stagesStart
- The latest status of every order25 min · 4 stagesStart
- A session funnel with repeated events30 min · 4 stagesStart
- Order totals without multiplying payments35 min · 4 stagesStart
- A running balance with quiet days35 min · 4 stagesStart
- Mature customer retention cohorts35 min · 4 stagesStart
- Local reporting dates from UTC events35 min · 4 stagesStart
- Deduplicating corrected transaction deliveries35 min · 4 stagesStart
Excel task talk-through
Explain a workbook, formulas, source checks and refresh without a spreadsheet test.
6 scenarios
Excel task talk-through
Explain a workbook, formulas, source checks and refresh without a spreadsheet test.
- Talk through a repeatable sales report30 min · 4 stagesStart
- A lookup with missing and repeated keys30 min · 4 stagesStart
- An Excel capacity plan talk-through30 min · 4 stagesStart
- Talk through a budget variance workbook30 min · 4 stagesStart
- Talk through a receivables aging report30 min · 4 stagesStart
- Talk through a weighted service summary30 min · 4 stagesStart
Metrics and A/B testing
Define an outcome, test competing explanations and decide what the evidence supports.
6 scenarios
Metrics and A/B testing
Define an outcome, test competing explanations and decide what the evidence supports.
- A checkout experiment with a guardrail30 min · 4 stagesStart
- A drop in onboarding completion30 min · 5 stagesStart
- A retention dashboard dispute30 min · 5 stagesStart
- Plan an experiment before collecting results30 min · 4 stagesStart
- A launch spike that fades30 min · 4 stagesStart
- An average that hides slower service30 min · 4 stagesStart
Data modeling
Choose fact grain, preserve history and reconcile data across sources.
6 scenarios
Data modeling
Choose fact grain, preserve history and reconcile data across sources.
- Subscription history at the right grain30 min · 4 stagesStart
- Orders, returns and a star schema30 min · 4 stagesStart
- A workforce model with transfers30 min · 4 stagesStart
- Inventory movements and daily balances30 min · 4 stagesStart
- Campaign tags without duplicated revenue30 min · 4 stagesStart
- Order lifecycle and missed milestones30 min · 4 stagesStart
Pipeline design and operations
Design incremental loads, backfills, schema changes and freshness controls.
6 scenarios
Pipeline design and operations
Design incremental loads, backfills, schema changes and freshness controls.
- An incremental invoice load30 min · 4 stagesStart
- A schema change during a backfill30 min · 4 stagesStart
- A fresh-looking stale dashboard30 min · 4 stagesStart
- Late events in a streaming metric30 min · 4 stagesStart
- A daily load with uneven source arrivals30 min · 4 stagesStart
- Repair a partition without stopping current data30 min · 4 stagesStart
Coding interviews
Write and run code, test edge cases, and explain correctness and time and space costs.
6 scenarios
Coding interviews
Write and run code, test edge cases, and explain correctness and time and space costs.
- Explain an interval merge30 min · 4 stagesStart
- Deduplicate a bounded event stream30 min · 4 stagesStart
- Explain a top-k counter30 min · 4 stagesStart
- Summarize a large CSV in Python30 min · 4 stagesStart
- Sessionize user events in Python30 min · 4 stagesStart
- Choose the latest record in Python30 min · 4 stagesStart
Process and requirements
Observe a workflow, resolve definitions and specify testable acceptance criteria.
6 scenarios
Process and requirements
Observe a workflow, resolve definitions and specify testable acceptance criteria.
- Requirements for a request handoff30 min · 4 stagesStart
- A process bottleneck30 min · 4 stagesStart
- Acceptance criteria for a reporting change30 min · 4 stagesStart
- Define a service-level clock30 min · 4 stagesStart
- Map a rework loop before changing staffing30 min · 4 stagesStart
- Acceptance criteria for a workflow migration30 min · 4 stagesStart
Finance and valuation
Walk through statements, a DCF and comparable valuation with explicit assumptions.
6 scenarios
Finance and valuation
Walk through statements, a DCF and comparable valuation with explicit assumptions.
- A three-statement accounting technical30 min · 4 stagesStart
- A DCF from cash flow to equity30 min · 4 stagesStart
- Comparable valuation and an earnings adjustment30 min · 4 stagesStart
- Profit growth with a cash shortage30 min · 4 stagesStart
- A driver-based operating forecast30 min · 4 stagesStart
- A compact DCF calculation30 min · 4 stagesStart
Accounting and reconciliations
Explain entries, cutoff, source evidence and a reconciliation without a plug.
6 scenarios
Accounting and reconciliations
Explain entries, cutoff, source evidence and a reconciliation without a plug.
- A bank reconciliation without a plug30 min · 4 stagesStart
- Accruals, deferrals and the close30 min · 4 stagesStart
- A duplicate invoice and a credit30 min · 4 stagesStart
- An unbilled service at month-end30 min · 4 stagesStart
- Equipment and support revenue30 min · 4 stagesStart
- A close with an unsupported reconciliation30 min · 4 stagesStart
Product judgment
Practice product sense, metrics, prioritization and a driver-based estimate.
6 scenarios
Product judgment
Practice product sense, metrics, prioritization and a driver-based estimate.
- Product sense for a booking problem30 min · 4 stagesStart
- A search metric that can mislead30 min · 4 stagesStart
- Prioritization with uncertain estimates30 min · 4 stagesStart
- Estimate a service’s capacity need30 min · 4 stagesStart
- A release with a broken core journey30 min · 4 stagesStart
- A new-user retention decline30 min · 4 stagesStart
Workforce and HR reporting
Define headcount and turnover, reconcile HR systems and protect sensitive records.
6 scenarios
Workforce and HR reporting
Define headcount and turnover, reconcile HR systems and protect sensitive records.
- A workforce turnover definition30 min · 4 stagesStart
- An HR system reporting mismatch30 min · 4 stagesStart
- Headcount, FTE and available hours30 min · 4 stagesStart
- Compare new-hire attrition fairly30 min · 4 stagesStart
- An employee survey with uneven response30 min · 4 stagesStart
- A corrected transfer in a headcount report30 min · 4 stagesStart
Capacity and project trade-offs
Plan around scarce skills, dependencies, changes and uncertain delivery dates.
6 scenarios
Capacity and project trade-offs
Plan around scarce skills, dependencies, changes and uncertain delivery dates.
- A specialist shared by two projects30 min · 4 stagesStart
- A change request near delivery30 min · 4 stagesStart
- A dependency with no reliable date30 min · 4 stagesStart
- A schedule with parallel dependencies30 min · 4 stagesStart
- A delivery team with uneven skills30 min · 4 stagesStart
- A launch with a quantified supplier risk30 min · 4 stagesStart
IT service management
Restore an incident, control an emergency change and investigate recurrence.
6 scenarios
IT service management
Restore an incident, control an emergency change and investigate recurrence.
- An incident with uncertain impact30 min · 4 stagesStart
- An emergency change decision30 min · 4 stagesStart
- Recurring incidents and problem management30 min · 4 stagesStart
- An SLA report with excluded tickets30 min · 4 stagesStart
- A planned change with a dependency conflict30 min · 4 stagesStart
- A recurring queue failure30 min · 4 stagesStart
Preparation
Each problem includes lesson links and a junior, mid, and senior rubric. Presentation practice uses work you describe in the shared notes. Keep personal and employer information out of your answers.
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