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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.
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Showing 2791–2820 of 3640 results
- PinterestMediumData ScientistDesign Algorithm to Minimize Payments in Expense-Sharing App
This question evaluates algorithm design and optimization skills, focusing on modeling multi-party transactions and minimizing the number of settlement operations.
Coding & AlgorithmsOnsite - PinterestHardSoftware EngineerDesign Bulk CSV and Individual Record Updates with Reliable, Partitioned Processing
A system design question about letting customers update records individually and in bulk by uploading CSV files. It focuses on reliable asynchronous job processing, idempotent row application, partitioning large files and the underlying data, conflicts between the two write paths, and reporting row outcomes.
System DesignOnsite - PinterestHardSoftware EngineerDesign Comment Notifications with Viral-Pin Aggregation
Tests end-to-end system design for large-scale, bursty notification pipelines, focusing on stream processing, aggregation under viral traffic spikes, and reliable third-party push delivery.
System DesignOnsiteDistributed SystemsStream ProcessingMessage Queues - PinterestMediumData ScientistDesign Data Structure for Sparse Matrices Operations
This question evaluates a candidate's ability to design efficient data structures and implement algorithms for sparse matrix storage and operations, emphasizing space-efficient representations, matrix arithmetic, and computational complexity reasoning.
Coding & AlgorithmsOnsite - PinterestMediumMachine Learning EngineerDesign Detection Systems for Risk and Safety
This question tests the ability to design an end-to-end classification system for detecting harmful content (e.g., spam or toxic images) while balancing precision and recall at scale.
ML System DesignOnsiteComputer VisionNLPContent Moderation - PinterestHardSoftware EngineerDesign Individual and Bulk Merchant Product Updates with Image Uploads
This problem tests the ability to design a distributed system capable of handling high-throughput asynchronous updates, atomic transactional integrity for partial batch failures, and robust image processing pipelines.
System DesignOnsiteAsynchronous ProcessingConcurrencyScalability - PinterestHardSoftware EngineerDesign Pin recommendation system
This question evaluates ability to design a large-scale personalized home feed recommendation system, testing skills in ML system design, recommender algorithms, retrieval and ranking architectures, feature engineering, data pipelines, low-latency serving, evaluation metrics, safety, and privacy.
ML System DesignOnsite - PinterestHardSoftware EngineerDesign Real-Time Search Autocomplete with Top-10 Popularity-Ranked Prefix Suggestions
Design a distributed search autocomplete system capable of returning the top 10 popularity-ranked queries for any prefix with sub-30ms latency. The problem evaluates your ability to handle massive read throughput, partition heavily skewed prefix workloads, and merge streaming popularity signals with batch historical baselines.
System DesignOnsiteDistributed SystemsSearchCaching - PinterestMediumMachine Learning EngineerDesign User and Item Embeddings from Long Histories
Design an end-to-end candidate retrieval system using user and visual-item embeddings capable of processing ultra-long user histories (up to 160,000 interactions) while handling real-time freshness, cold-start items, and privacy constraints.
ML System DesignOnsiteRecommendation SystemsVector EmbeddingsCandidate Retrieval - PinterestHardSoftware EngineerDesign a Google Photos–like service
This question evaluates proficiency in designing large-scale distributed media systems, testing competencies in distributed storage and caching, ingest pipelines, CDN-backed delivery, indexing/search, sync/conflict resolution, access control/privacy compliance, and cost/operational planning.
System DesignOnsite - PinterestMediumSoftware EngineerDesign a Large-File Upload and Analysis Flow
Tests the ability to design an end-to-end media ingestion system supporting chunked resumable uploads, asynchronous analysis pipelines, idempotency, and real-time client notifications.
System DesignOnsitesystem-designcloud-storagedistributed-systems - PinterestMediumSoftware EngineerDesign a Low-Latency Typeahead Service
This problem tests the ability to design a high-throughput, low-latency search suggestion system that handles real-time updates and ranking at scale.
System DesignOnsiteCachingDistributed SystemsSearch - PinterestHardSoftware EngineerDesign a Merchant Catalog Update Pipeline with Bulk Files and Image Resizing
Tests the ability to architect a scalable, asynchronous catalog ingestion pipeline that balances high-throughput bulk feed processing with low-latency single-item edits while prioritizing price and inventory updates over compute-heavy image processing.
System DesignOnsiteDistributed SystemsData PipelinesMessage Queues - PinterestHardSoftware EngineerDesign a Typeahead Service on an In-Memory Trie, Then Scale It Without New Services
Design a typeahead autocomplete service that starts at a modest scale using an in-memory keyword trie, then scale it out without adding external services. It tests trie internals and keyword storage, read and write paths, score updates, rebuilds with hot swaps, and sharding strategy trade-offs.
System DesignOnsite - PinterestEasySoftware EngineerDesign a Typeahead Suggestion System
Design a low-latency, real-time typeahead suggestion system that handles prefix search, query ranking, aggressive caching, and stale response mitigation.
System DesignOnsitesystem-designtrietypeahead - PinterestHardSoftware EngineerDesign a high-throughput distributed rate limiter
Pinterest software-engineer onsite system-design question: design a multi-region, high-throughput distributed rate limiter targeting ~10M req/s with per-user, per-API, and global limits, burst tolerance, and an approximately-sliding window. It tests token-bucket/GCRA algorithm choice, an architecture of local in-process buckets fed by epoch-based token leases, consistent-hashing sharding with hot-key splitting, bounded-overshoot consistency, fault handling, fairness, capacity-planning math (including a 2× spike), backpressure, and observability.
System DesignOnsite - PinterestHardMachine Learning EngineerDesign a real-time home feed ranker
This problem evaluates your ability to design a multi-stage recommendation architecture capable of integrating real-time user signals, managing feature latency, and balancing ranking accuracy with system throughput.
ML System DesignOnsiteSystem DesignRecommendation SystemsReal-time - PinterestMediumSoftware EngineerDesign adjustable ID allocator
A Pinterest software-engineer onsite coding problem: design an adjustable ID allocator over a fixed [0, 999] ID space with named, contiguous, non-overlapping bucket ranges. It covers initial allocation (packing from desired sizes and validating/normalizing proposed ranges), a resize operation that grows or shrinks a bucket by consuming adjacent free space and then minimally shifting or borrowing from neighbors under a deterministic policy, plus complexity analysis, boundary-case testing, and concurrency handling.
Coding & AlgorithmsOnsite - PinterestHardSoftware EngineerDesign an Ad Click Aggregator for Last-Year Counts Using an Existing Logging API
A system design question about an ad click aggregator whose queries cover the last year rather than the last few minutes and which must take its click data from an existing logging API. It tests requirement clarification, checkpointed ingestion and backfill, deduplication, rollup storage, and correcting historical counts.
System DesignOnsite - PinterestMediumSoftware EngineerDesign an ads event reporting system
This question tests the ability to design a high-throughput, fault-tolerant system for tracking ad interaction events, focusing on scalability, exactly-once processing, and analytical query performance.
System DesignOnsiteScalabilityData PipelinesAnalytics - PinterestHardMachine Learning EngineerDesign an unsafe content detection system
This problem evaluates your ability to design a scalable, multimodal machine learning pipeline for detecting policy-violating content on a large-scale visual discovery platform.
ML System DesignOnsiteMultimodal LearningReal-time InferenceContent Moderation - PinterestMediumSoftware EngineerDesign highly available blob storage service
This question evaluates a candidate's competency in designing scalable, durable, and highly available blob/object storage systems, encompassing distributed systems architecture, data modeling for buckets and objects, metadata management, partitioning and routing, fault tolerance strategies, consistency models, large-object transfer patterns, security controls, and operational concerns like monitoring and capacity planning. Commonly asked in the System Design domain to assess practical application of architectural patterns and trade-offs—horizontal scalability, durability versus latency, consistency guarantees, and operational resilience—it primarily tests practical system-design skills grounded in conceptual understanding of distributed systems.
System DesignOnsite - PinterestMediumMachine Learning EngineerDesign notification and feed recommenders
This question tests the ability to design a dual-purpose recommendation architecture capable of handling real-time push notifications and personalized feed updates at scale.
ML System DesignOnsiteRecommender SystemsRankingScalability - PinterestHardData ScientistDesign rigorous A/B test and causal analysis
This question evaluates a data scientist's competency in experimental design, sample-size and power calculations, variance-reduction methods (e.g., CUPED), sequential testing and alpha spending, clustering and interference effects, SRM checks, and causal identification strategies such as DID, IV, and RDD within the Statistics & Math domain.
Statistics & MathOnsite - PinterestMediumData ScientistDetermine Pin Connections Through Common Boards
This question evaluates graph modeling and connectivity concepts, including representing boards and pins as relationships and reasoning about reachability and minimal connection paths.
Coding & AlgorithmsOnsite - PinterestHardData ScientistDiagnose CTR drop after recommendation launch
This question evaluates a data scientist's competency in experiment diagnosis, metric and guardrail definition, instrumentation validation, segmentation analysis, and causal reasoning for recommender-system impacts.
Analytics & ExperimentationOnsite - PinterestMediumData ScientistEstimate a Launch Impact with Difference in Differences
Tests your ability to design and evaluate a regional quasi-experiment using Difference-in-Differences (DiD), validate key identifying assumptions, structure robust inference, and address modern complications such as staggered rollout and network spillovers.
Analytics & ExperimentationOnsiteDifference-in-DifferencesCausal InferenceQuasi-Experiments - PinterestHardData ScientistEstimate billboard reach and impressions
This question evaluates probabilistic modeling and statistical inference skills applied to audience measurement and attribution, covering Poisson-based frequency modeling, visibility-adjusted impressions, panel-based deduplication and expansion, uncertainty propagation (delta method/bootstrap), and Markov-chain attribution within the Statistics & Math / Data Science domain. It is commonly asked to test the ability to convert traffic and visibility inputs into quantitative reach and impressions with propagated confidence intervals, reason about attribution via a 3-state Markov chain, identify measurement biases, and demonstrates both conceptual understanding and practical application through numerical estimation and sensitivity analysis.
Statistics & MathOnsite - PinterestMediumData ScientistEvaluate New Feed-Ranking Algorithm with A/B Testing
Pinterest experimentation prompt on evaluating a new feed-ranking algorithm, covering A/B hypotheses, daily active minutes, guardrails, sample size, MDE, experiment health, mid-test dips, and geo-based causal inference.
Analytics & ExperimentationOnsite - PinterestMediumSoftware EngineerFewest Buses to Ride Between Two Stops on Looping Bus Lines
A coding problem about bus lines that loop through fixed lists of stops: find the fewest buses a rider must board to travel from a source stop to a target stop, or report that the target cannot be reached. It tests modeling transfers between lines as a graph and keeping the search efficient when many lines share stops.
Coding & AlgorithmsOnsite
Pinterest