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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
- Questions
- 546
- Companies
- 11
- Topics
- 8
- Languages
Showing 151–180 of 9403 results
- AirbnbHardSoftware EngineerDesign a scalable consumer feature
This question evaluates a candidate's ability to design large-scale recommendation systems, covering system architecture, real-time serving and offline pipelines, personalization and ML modeling (candidate generation and ranking), data modeling/feature stores, caching and storage, monitoring, experimentation, and privacy/compliance skills.
System DesignOnsite - AirbnbHardSoftware EngineerDesign an A/B Testing Platform
Design an A/B testing platform with deterministic assignment, versioned experiment configuration, exposure logging, outcome attribution, and trustworthy analysis. Separate the latency-sensitive serving path from asynchronous metrics, support gradual ramps and overlapping tests, and detect bias, event loss, skew, and sample-ratio mismatch.
System DesignOnsite - AirbnbHardData ScientistDesign an A/B test with causal inference
This question evaluates skills in experimental design, causal inference, and applied statistics — including estimand selection, sample-size calculation under clustering, integrity monitoring, handling noncompliance and contamination, sequential monitoring, and two-proportion inference — within the Analytics & Experimentation domain for a Data Scientist role. It is commonly asked because interviewers need to assess the ability to design and analyze robust A/B tests under real-world constraints; the prompt requires both conceptual understanding of causal assumptions and practical application of power calculations, diagnostics, and monitoring procedures.
Analytics & ExperimentationTechnical Screen - AirbnbHardSoftware EngineerDesign an Airbnb wallet with holds and payouts
This question evaluates a candidate's competency in designing financial transaction systems, covering double-entry append-only ledgers, holds/authorizations and captures, refunds and payouts, multi-currency FX conversion and rounding, idempotency, concurrency safety, and auditable reconciliation.
System DesignTechnical Screen - AirbnbEasySoftware EngineerDesign an In-Memory Cloud Storage Service with Users, Backups, and Restore
Implement an in-memory cloud storage system supporting user storage limits, globally unique files, ranked file queries, account merges, and transactional backup and restore operations.
Software Engineering FundamentalsOnline AssessmentObject-Oriented DesignData StructuresHash Table - AirbnbMediumSoftware EngineerDesign an extensible request Retryer
This question evaluates a candidate's ability to design extensible and robust retry mechanisms, covering competencies in API/interface design, fault tolerance, backoff and jitter strategies, cancellation/deadline handling, idempotency considerations, and observability.
Software Engineering FundamentalsTechnical Screen - AirbnbMediumData ScientistDesign and Analyze Airbnb Locker Experiment
This question evaluates a candidate's skills in experimental design and causal inference for marketplace features, including selecting the appropriate randomization unit, defining eligibility and treatment/control arms, and choosing primary, secondary, and guardrail metrics.
Analytics & ExperimentationTechnical Screen - AirbnbHardData ScientistDesign and assess an A/B test
This problem tests your ability to design a statistically sound A/B test for a marketplace platform, including metric selection, power analysis considerations, and handling potential interference effects.
Analytics & ExperimentationOnsiteA/B TestingExperimental DesignMetrics - AirbnbMediumSoftware EngineerDesign and implement Connect Four engine
This question evaluates a candidate's competency in algorithmic problem solving, data structure selection, API design, complexity analysis, and testing through implementation of a Connect Four game engine.
Coding & AlgorithmsTechnical Screen - AirbnbMediumSoftware EngineerDesign and implement an Airbnb wallet
This question evaluates system design and object-oriented design skills focused on transactional accounting, escrow-based payment flows, idempotency, and robust error handling, plus the ability to produce a runnable in-memory implementation.
System DesignTechnical Screen - AirbnbHardSoftware EngineerDesign multi-currency pricing end-to-end
This question evaluates understanding of multi-currency pricing and payments, covering currency selection UX, storage versus presentation currency, exchange-rate sourcing and locking, rounding and localization, tax and fee modeling, caching and cross-channel consistency, and API and data-model design in a distributed marketplace.
System DesignOnsite - AirbnbMediumSoftware EngineerDesign mutable sum-tree with fast queries
This question evaluates proficiency in designing dynamic data structures for mutable rooted trees, including maintenance of subtree sums, parent/child link management, and analysis of update and query complexities within the Coding & Algorithms domain; it emphasizes practical application of algorithmic design coupled with conceptual understanding of invariants and amortized complexity. It is commonly asked in technical interviews because it probes reasoning about correctness and performance under mutations, handling edge cases such as subtree deletion and reattachment, and the ability to specify algorithmic approaches and complexity guarantees rather than implementation details.
Coding & AlgorithmsOnsite - AirbnbMediumMachine Learning EngineerDesign photo and listing quality models
This question tests the end-to-end design of a machine learning system to evaluate the quality of listing photos and overall listing attractiveness to improve search ranking and conversion.
Machine LearningOnsiteComputer VisionRanking SystemsFeature Engineering - AirbnbHardSoftware EngineerDesign rental watchlist and notification system
This question evaluates system architecture and scalability competencies, including data modeling for date-range watchlists, event-driven notification pipelines, time-zone and DST handling, consistency and concurrency semantics, idempotency, sharding/caching strategies, and privacy/analytics considerations.
System DesignOnsite - AirbnbHardData ScientistDesign robust primary and guardrail metrics
This question evaluates proficiency in experiment metric design, guardrail definition, data quality diagnostics, and statistical analysis for A/B testing, including power calculations and sequential monitoring, within the Analytics & Experimentation domain.
Analytics & ExperimentationTechnical Screen - AirbnbHardSoftware EngineerDesign scalable notification system
Airbnb's onsite system design round asks you to design a notification system that delivers email, SMS, and push messages to millions of guests, hosts, and employees, supporting both event-triggered sends and large batch campaigns. A complete answer covers requirements and scale math, architecture and data flow for both modes, the data model and API, templating, user preferences and compliance, prioritization, deduplication and idempotency, retries and failover, scaling and backpressure, observability, and cost. This walkthrough gives a corrected end-to-end reference answer for every part, including the trade-offs interviewers probe.
System DesignOnsite - AirbnbHardSoftware EngineerDetect overlap of two linked lists with cycles
This problem tests your ability to detect if two linked lists merge, specifically when they may contain cycles, by requiring logic to identify loop entry points and intersection nodes.
Coding & AlgorithmsOnsiteLinked ListTwo PointersCycle Detection - AirbnbMediumSoftware EngineerDetermine Exact Layover Booking
Determine if a subset of layover activities can be booked such that their total cost exactly matches a target voucher balance, handling floating-point currency without precision loss.
Coding & AlgorithmsTechnical ScreenDynamic ProgrammingBacktrackingSubset Sum - AirbnbMediumMachine Learning EngineerDiscuss ML Project Tradeoffs
This question evaluates a candidate's skills in model selection, trade-off analysis between precision, recall, latency and infrastructure cost, threshold tuning, reconciliation of offline versus online metrics, and comparative understanding of recommendation models within the Machine Learning domain.
Machine LearningOnsite - AirbnbMediumSoftware EngineerDiscuss learning and feedback experiences
This interview question evaluates behavioral evidence, ownership, communication, trade-offs, and measurable outcomes in a realistic interview setting. A strong answer for Discuss learning and feedback experiences states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Behavioral & LeadershipTechnical Screen - AirbnbHardData ScientistEstimate Causal Impact Using Synthetic Control Methods
Evaluates causal impact estimation after a full product rollout with no holdout. Strong answers use interrupted time series, synthetic control, Bayesian structural time series, exposure variation, and placebo tests to build and validate a credible counterfactual.
Analytics & ExperimentationTechnical Screen - AirbnbMediumData EngineerEstimate Page-Visit Duration from the Next User Event
Implement logic to compute user page-visit durations based on adjacent event timestamps, deterministically resolving ties and handling boundary conditions for terminal events.
Data Manipulation (SQL/Python)Onsitepythonsqldata-manipulation - AirbnbHardData ScientistEstimate impact of global launch without holdout
This question evaluates a candidate's competence in causal inference, observational study design, and statistical uncertainty quantification for product analytics, specifically estimating lift after a global launch without a holdout while addressing confounding, interference, and operational data-quality issues.
Analytics & ExperimentationTechnical Screen - AirbnbMediumMachine Learning EngineerExplain ML Project Milestones, Scope, and Conflict
Explain an ML project through scope decisions, measurable milestones, stakeholder conflict, online readiness, and evidence-based changes to the plan.
Behavioral & LeadershipOnsite - AirbnbMediumSoftware EngineerExplain why you want to join Airbnb
This question evaluates a software engineer's ability to articulate authentic motivation, product literacy, and cultural fit in a values-focused interview round. It tests how well candidates can connect their engineering background to real organizational problems and communicate genuine alignment — skills commonly assessed in the culture and behavioral rounds of technical interview loops.
Behavioral & LeadershipTechnical Screen - AirbnbMediumData EngineerFind Hosts Meeting Listing, Rating, and Review-Coverage Rules
Tests the ability to write a SQL query performing multi-table aggregations, date-windowed conditional logic, and host-level qualification filtering across listing counts, average ratings, and recent review coverage.
Data Manipulation (SQL/Python)Onsitesqlaggregationconditional-logic - AirbnbMediumData EngineerFind Users with Seven Consecutive Impression Days
Tests your ability to identify consecutive calendar-day activity streaks in PostgreSQL using window functions, date arithmetic, and deduplication.
Data Manipulation (SQL/Python)Onsitesqlpostgresqlwindow-functions - AirbnbMediumSoftware EngineerFind minimal property set in neighborhood
This question evaluates combinatorial optimization and algorithm design skills, focusing on capacity-constrained selection (subset-sum/knapsack-style reasoning), deterministic tie-breaking, and complexity analysis within the Coding & Algorithms domain.
Coding & AlgorithmsTechnical Screen - AirbnbMediumSoftware EngineerFind palindrome-forming string pairs
This question evaluates string-processing and algorithmic design skills, including knowledge of efficient lookup data structures, palindrome properties, handling of edge cases, and time/space complexity analysis.
Coding & AlgorithmsOnsite - AirbnbMediumSoftware EngineerFind smallest permutation under constraints
This problem tests your ability to manipulate digits and understand greedy strategies to construct the smallest possible number after applying specific constraints.
Coding & AlgorithmsOnsiteGreedyRecursionStrings
Airbnb