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Interview Questions
Practice 9403 coding, system design and machine learning questions from 546 companies, sorted by role, topic and interview round. Every question has step-by-step hints, a code runner that supports 8 languages and an AI mentor; members also get the full solution walkthrough.
- 9403
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- 546
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- 11
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Showing 4171–4200 of 9403 results
- InstacartMediumSoftware EngineerBuild a Progressive Banking System
This problem tests your ability to manage state transitions, handle expiring reservations, and maintain consistent ledger balances across multiple accounts.
Coding & AlgorithmsTechnical ScreenHash MapState ManagementTransaction Processing - InstacartMediumData ScientistCalculate Weekly Revenue and Order Count for Standard Deliveries
This question evaluates proficiency in time-based aggregations and filtering on order-level transactional data to compute weekly revenue and order counts specifically for standard delivery orders.
Data Manipulation (SQL/Python)Technical Screen - InstacartMediumSoftware EngineerCalculate a Basket Total from Delimited Product Records
Parse pipe-delimited shopping cart records to compute the total basket cost in integer cents, properly accumulating repeated SKUs and handling zero-quantity items.
Coding & AlgorithmsOnsitestringsparsinghash-table - InstacartHardData ScientistChoose tests under non‑normal, unequal variance
This question tests the ability to select and justify statistical inference methods for metrics that violate standard parametric assumptions, specifically when dealing with heavy-tailed, heteroskedastic, and zero-inflated distributions.
Statistics & MathOnsiteStatisticsA/B TestingInference - InstacartMediumSoftware EngineerCompute and optimize average wait time
This question evaluates skills in scheduling and queueing algorithms, simulation of service systems, and reasoning about time and space complexity when computing average waiting times.
Coding & AlgorithmsOnsite - InstacartMediumSoftware EngineerCompute average customer waiting time
Compute average customer waiting time evaluates algorithm design, data structures, correctness, complexity, edge cases, and implementation details in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Coding & AlgorithmsOnsite - InstacartMediumSoftware EngineerCompute delivery wait times
This question evaluates competence in event-driven simulation, scheduling and queueing concepts, and algorithmic analysis by requiring computation of average customer waiting time for single and multiple shoppers.
Coding & AlgorithmsOnsite - InstacartHardData ScientistCompute duration and stopping rules correctly
This question evaluates a data scientist's competency in experimental design and applied statistics, specifically power and sample‑size calculations, accounting for intra‑household clustering and design effects, sequential monitoring for peeking control, and variance‑reduction or stratified randomization to handle day‑of‑week seasonality.
Analytics & ExperimentationOnsite - InstacartMediumBackend EngineerDebug Metrics Computed Before Filtering
Debug a metrics endpoint whose summary is calculated before user filters are applied even though its rows are filtered correctly. Trace the data lineage, aggregate over the full matched population before pagination, preserve security scoping, and add unit and endpoint regression tests.
Software Engineering FundamentalsOnline Assessment - InstacartEasySoftware EngineerDebug Search and Stock Behavior in a Library Application
Debug a library application’s incomplete search and stock displays by reproducing symptoms, tracing API behavior, checking query semantics, and validating focused fixes.
Software Engineering FundamentalsOnline Assessment - InstacartHardSoftware EngineerDecode a password string into letters
This problem tests your ability to parse and reconstruct a string based on specific numeric encoding rules, requiring careful index tracking and stack-based or recursive logic.
Coding & AlgorithmsTechnical ScreenStringsStackRecursion - InstacartMediumSoftware EngineerDecode an encoded string
This question evaluates string parsing and manipulation skills, particularly handling nested repetition encodings and managing state when expanding bracketed substrings.
Coding & AlgorithmsTechnical Screen - InstacartMediumSoftware EngineerDescribe your most complex end-to-end project
Describe your most complex end-to-end project evaluates behavioral evidence, ownership, communication, trade-offs, and measurable outcomes in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Behavioral & LeadershipHR Screen - InstacartMediumBackend EngineerDesign Idempotent Due-Date and Hold Notifications
Design idempotent library notifications for upcoming and current due dates plus FIFO hold availability. Use stable business-event identities, transactional scheduling, atomic recipient claims, state rechecks, retries, reconciliation, and clear frontend distinctions among holds, offers, and checkouts.
System DesignOnline Assessment - InstacartMediumSoftware EngineerDesign Idempotent In-App Availability and Due-Date Notifications
Design asynchronous in-app availability alerts and due-date reminders with Celery, Redis, durable idempotency, versioned schedules, and crash recovery.
System DesignOnline Assessment - InstacartHardSoftware EngineerDesign a bus simulation metric
This problem tests your ability to design a telemetry metric for a simulation environment, requiring you to define efficiency, implement instrumentation within existing logic, and explain how to validate the metric's accuracy.
Software Engineering FundamentalsOnsiteSystem DesignInstrumentationSimulation - InstacartEasyData ScientistDesign a pricing experiment with network effects
This question evaluates experimental design and causal inference competencies for a two-sided marketplace pricing change, including handling network effects/interference, choice of unit of randomization and treatment markets, metric selection and diagnostics, power/MDE estimation, and operational risk assessment within the Analytics & Experimentation domain for a Data Scientist role. It is commonly asked to assess practical application of randomized and quasi-experimental methods across heterogeneous geographies and operational constraints, requiring both hands-on experimental design skills and conceptual understanding of bias, spillovers, and diagnostic metrics.
Analytics & ExperimentationTechnical Screen - InstacartMediumSoftware EngineerDesign a task system with assignments
This question tests your ability to design a flexible data model for a task-assignment system, focusing on efficient lookups and state management in an in-memory environment.
Software Engineering FundamentalsTechnical ScreenSystem DesignData StructuresAPI Design - InstacartMediumSoftware EngineerDesign an Inventory Service with Reservations, Hot SKUs and Oversell Prevention
A system design question about an inventory management service that reserves stock while customers check out. It tests how a candidate prevents overselling under concurrent updates, handles hot SKUs, manages reservation expiry and idempotency, and supports partial fulfillment of multi-item orders.
System DesignOnsite - InstacartMediumSoftware EngineerDesign an Inventory Service with Stock Reservations That Prevents Overselling
A system design discussion of an inventory service that reserves stock for orders, centered on reservations, concurrent updates and preventing overselling. It probes how stock and holds are modeled, how a reservation stays atomic under contention, how abandoned holds are released and how hot items scale.
System DesignTechnical Screen - InstacartMediumSoftware EngineerDesign an inventory management system
This question evaluates competency in system design, data modeling, distributed consistency, concurrency control, API design, idempotency, and scalability for backend inventory and reservation workflows.
System DesignOnsite - InstacartMediumSoftware EngineerDesign an inventory system
This question evaluates a candidate's competency in designing inventory and distributed systems, covering stock tracking models, reservation and commit semantics, concurrency control, data modeling, API design, and real-time integrations.
System DesignHR Screen - InstacartHardData ScientistDesign and Interpret an A/B Test
This question tests the ability to design a statistically rigorous A/B test, calculate sample sizes based on effect thresholds, and account for real-world constraints like seasonality and multiple comparisons.
Analytics & ExperimentationOnsiteA/B TestingPower AnalysisStatistics - InstacartMediumSoftware EngineerDesign and Release a Consistent Dark-Store Inventory System
Design a strongly consistent micro-fulfillment (dark-store) inventory system that handles reservations, stock reconciliation, and idempotent retries, alongside a zero-downtime deployment strategy.
System DesignOnsitesystem-designdistributed-transactionsinventory-management - InstacartHardSoftware EngineerDesign cloud storage with quotas and compression
This question evaluates a candidate's ability to design a multi-tenant cloud storage system, testing competencies in API design, quota accounting, compression strategies, distributed storage architecture (partitioning, replication/erasure coding), consistency models, security, versioning, and observability.
System DesignOnline Assessment - InstacartHardSoftware EngineerDesign product catalog service
This interview question evaluates requirements, scale assumptions, API/data design, architecture, trade-offs, failure modes, and rollout in a realistic interview setting. A strong answer for Design product catalog service states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
System DesignOnsite - InstacartHardSoftware EngineerDesign scalable inventory system and avoid races
This question evaluates a candidate's ability to design scalable, highly available distributed systems with robust concurrency control and consistency reasoning, covering architecture, data modeling, caching, message-based integration, and operational concerns like observability and disaster recovery.
System DesignOnsite - InstacartMediumData ScientistDiagnose and fix low conversion rigorously
This question evaluates a Data Scientist's competency in analytics and experimentation, covering instrumentation validation, funnel and segmentation analysis, causal inference methods (holdouts/DiD), system reliability diagnostics, statistical power and sample-size estimation, and the ability to synthesize findings into executive-level impact statements. It is commonly asked to determine whether a candidate can distinguish measurement or product regressions from marketing-mix shifts and to demonstrate both conceptual understanding of causal inference and practical application of data querying, metric definition, and experiment design in the Analytics & Experimentation domain.
Analytics & ExperimentationHR Screen - InstacartMediumSoftware EngineerDiscuss an Interesting Project and a Deployment Mistake
Tests an engineer's ability to articulate complex technical architecture, evaluate architectural tradeoffs, take ownership of production failures, and demonstrate long-term operational growth.
Behavioral & LeadershipOnsitebehavioralsystem-reliabilityproduction-incidents - InstacartEasySoftware EngineerEvaluate Ordered Variable Definitions with Addition and Subtraction
Evaluate ordered variable definitions and plus/minus expressions with an explicit directional grammar, while distinguishing assignment lookup from general equation solving.
Coding & AlgorithmsOnsite
Instacart