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System Design 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 991–1020 of 1311 results
- 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 - 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 - 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 - PinterestHardSoftware EngineerKeep Merchant Addresses, Social Followers, and Wiki Facts Up to Date
Design a high-scale merchant data enrichment platform that ingests, reconciles, and maintains up-to-date business attributes (addresses, social metrics, wiki metadata) across heterogeneous third-party sources with strong provenance and fault tolerance.
System DesignOnsitesystem-designdistributed-systemsdata-pipelines - PinterestHardSoftware EngineerScheduling Four Apps at Once on Kubernetes and a Node-Feedback Scheduler Plugin
A Kubernetes scheduling exercise for a senior infrastructure role: four applications request scheduling at the same time, and the candidate must ask the questions that settle capacity, priority, placement and coordination, then commit to a plan. A second part designs a scheduler plugin that uses signals reported by nodes.
System DesignTechnical Screen - PlaidEasySoftware EngineerDesign a ChatGPT-like conversational assistant
This question evaluates a candidate's ability to design large-scale conversational AI systems, covering competencies in distributed system architecture, real-time streaming, stateful multi-turn session management, safety controls, and integration with external tools.
System DesignTechnical Screen - PlaidEasySoftware EngineerDesign a geo-distributed rate limiter
This question evaluates a candidate's competency in designing geo-distributed, globally consistent rate limiting systems that enforce per-API-key and additional constraints while balancing low-latency request paths and regional failure tolerance.
System DesignTechnical Screen - PlaidMediumSoftware EngineerDesign an Embeddable Pay by Bank Widget
Design a secure, embeddable Pay by Bank frontend widget and supporting backend infrastructure that enables direct bank checkout via an isolated iframe and asynchronous payment processing.
System DesignOnsiteSecurityWeb ArchitecturePayments - Point72HardData EngineerDesign Data Quality and Observability Pipeline
This question evaluates proficiency in designing production data orchestration, data quality validation, and observability frameworks for both batch and streaming pipelines, covering dependency management, schema and integrity checks, and operational handling of anomalous records.
System DesignTechnical Screen - PosthogMediumSoftware EngineerDesign Product Analytics and Event Capture for a Small E-Commerce Store
Design analytics for a small independent e-commerce store, with the emphasis on how behavioral and purchase data is gathered in the first place. It tests event modeling, browser versus server-side capture, visitor identity across checkout, proportionate storage and funnel reporting, privacy, and data-quality reconciliation.
System DesignTechnical Screen - Qualified HealthHardSoftware EngineerControl LLM Workflow Quotas and Recovery Costs
Control LLM workflow quotas and 429 retries with shared token budgets, durable checkpoints, and explicit handling of uncertain requests and duplicate billing.
System DesignOnsite - Qualified HealthMediumSoftware EngineerDesign Notifications for One Million Internal Producer Services
Design notification ingestion and delivery for a million internal producers, separating service-count scale from throughput, bursts, and fanout.
System DesignOnline Assessment - Qualified HealthHardSoftware EngineerEnforce Tenant and Session Isolation in an Agent RAG System
Isolate tenants and sessions across RAG retrieval, caches, prompts, and tools, with server-enforced authorization and layered prompt-injection defenses.
System DesignOnsite - Qualified HealthHardSoftware EngineerIngest and Serve RAG Sessions with Up to 200 Documents
Design a 200-document RAG session pipeline with asynchronous ingestion, corpus readiness, latency budgeting, scoped caching, and quota-aware serving.
System DesignOnsite - Qualified HealthHardSoftware EngineerReconcile RAG Document Expiry, Chat History, and Cold Audits
Design 24-hour document deletion, seven-day chat history, fast sidebar reads, and cold audits while resolving conflicts over derived content and physical erasure.
System DesignOnsite - Qualified HealthHardSoftware EngineerRecover Durable Workflows with External Effects and Long Waits
Recover DAG workflows through crashes, duplicate attempts, external side effects, and multi-day approvals using durable state and explicit exactly-once limits.
System DesignOnsite - Qualified HealthHardSoftware EngineerScale Mixed I/O and LLM Workflow Execution
Scale mixed I/O and LLM workflows with separate worker budgets, tenant fairness, tiered state storage, and explicit reconciliation of conflicting workload figures.
System DesignOnsite - Qualified HealthHardSoftware EngineerStream LLM Output While Committing Reliable DAG Results
Stream provisional LLM output to clients while durably validating and committing complete structured results before downstream DAG tasks execute.
System DesignOnsite - Qualified HealthHardSoftware EngineerStream and Cancel Agent Responses Without Unsafe Retries
Design SSE or WebSocket streaming, end-to-end stop handling, and safe Agent retries while distinguishing local cancellation from provider billing and tool effects.
System DesignOnsite - Qualified HealthHardSoftware EngineerValidate Editable DAGs and Bound Runtime Repetition
Validate editable workflow DAGs, reason about cycle-check latency, and enforce durable retry and expansion limits that prevent unbounded runtime loops.
System DesignOnsite - Qube Research & TechnologiesHardSoftware EngineerDesign an asynchronous logger with formatting
This question evaluates expertise in concurrent programming, lock-free MPMC queue usage, producer–consumer asynchronous logging, variadic formatting APIs, and robustness in shutdown/flush semantics and error handling.
System DesignTechnical Screen - RampHardSoftware EngineerCount Visits in One Minute
This question evaluates a candidate's ability to design scalable, fault-tolerant real-time analytics systems for maintaining a sliding 60-second visitor count, covering competencies in event ingestion pipelines, deduplication, late-event handling, storage selection, scaling, and monitoring.
System DesignTechnical Screen - RampMediumSoftware EngineerDesign a Low-Latency Hotel Room Availability System
Design a high-throughput, low-latency room availability and reservation service that prevents double-booking while maintaining fast read times under heavy search traffic.
System DesignTechnical Screensystem-designcachingconcurrency - RampHardSoftware EngineerDesign a Payment-Count Dashboard That Scales with Readers and Updates
Tests candidate's ability to design a real-time, low-latency financial metrics dashboard that evolves from a simple relational database setup to a horizontally scalable, stream-aggregated architecture resilient to duplicate events and counter drift.
System DesignOnsitesystem-designdistributed-systemsstream-processing - RampMediumSoftware EngineerDesign a banking system with payments and merging
This question tests your ability to design a robust, distributed financial ledger system that handles high-throughput transactions, ensures strict consistency, and supports the complex operation of merging two distinct user accounts.
System DesignOnline AssessmentDistributed SystemsDatabasesFintech - RampHardSoftware EngineerDesign an in-memory cloud storage system
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 an in-memory cloud storage system states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
System DesignOnline Assessment - RapidSOSMediumSoftware EngineerDesign the Product Catalog for a Multi-Store Grocery Delivery Marketplace
A senior system design prompt reported from a RapidSOS loop: design the product catalog for a multi-store grocery delivery marketplace like Instacart. It tests modeling shared products versus per-store prices and availability, ingesting messy retailer feeds, store-scoped browse and search, caching, freshness and checkout consistency.
System DesignOther
Pinterest
Plaid
Point72
Qube Research & Technologies
Ramp