practice a little every day, paws crossed ♡
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.
- 9403
- Questions
- 546
- Companies
- 11
- Topics
- 8
- Languages
Showing 541–570 of 721 results
- 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 - 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 - 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 - 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 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 - 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 - RedditEasySoftware EngineerDesign a game leaderboard service
This question tests the ability to design a high-throughput, low-latency leaderboard service capable of handling frequent rank updates and read requests for millions of active users.
System DesignOnsiteCachingDatabasesScalability - RemitlyHardSoftware EngineerDesign a Production-Ready URL Shortener
This question evaluates competency in designing a scalable, reliable, and secure production URL shortening service, covering API design, link data modeling and analytics, ID/token generation, caching and read/write paths, partitioning/replication/consistency choices, rate limiting and abuse mitigation, TTL handling and cleanup, and HA/DR and monitoring. Commonly asked in system design interviews to probe architectural trade-offs for high-read consumer services, it belongs to the System Design domain and emphasizes practical application of distributed systems and operational concepts rather than only conceptual theory.
System DesignOnsite - RemitlyEasySoftware EngineerDesign an IP Address Filtering Service
Design a low-latency service that allows or denies traffic using source or destination IP rules. Candidates must define conflict precedence, address normalization, versioned rollout, stale-state behavior, audit evidence, privacy-conscious logging, and safe rollback.
System DesignOnsite - RemitlyHardSoftware EngineerWhiteboard and Deep Dive a Past Project
This question evaluates a candidate's end-to-end system design skills, including architecture decomposition, trade-off analysis, data consistency choices, scalability and resiliency patterns, and integration of operational practices for a user-facing distributed service.
System DesignOnsite - ReplitMediumSoftware EngineerDesign a Multi-Channel Notification System
Design a resilient, multi-channel notification service that routes notifications across in-app, email, SMS, and push channels while honoring user preferences, idempotency, rate limits, and provider status tracking.
System DesignOnsiteDistributed SystemsMessage QueuesAPI Design - Retell AIMediumSoftware EngineerDesign collaborative document editing backend
This question evaluates a candidate's ability to design real-time collaborative systems, focusing on distributed systems concepts, concurrency control, consistency models, synchronization, and scalable backend architecture.
System DesignOnsite - RipplingHardSoftware EngineerBuild Reliable Employee-Operations and Expense Intelligence Systems
A multi-part system-design interview covering tagged event aggregation, driver-pay accounting, employee offboarding, and an LLM-backed expense assistant. Candidates must distinguish approximate dashboards from exact billing and design reliable workflows across failing dependencies.
System DesignOnsite - RipplingHardSoftware EngineerDesign a Google News-like aggregator
This question evaluates system design skills for building a large-scale, multi-region news aggregation platform, assessing competencies in ingestion architecture, deduplication and clustering, indexing and retrieval, personalization and ranking, and operational concerns like monitoring, consistency, and compliance.
System DesignOnsite - RipplingHardSoftware EngineerDesign a Hotel Booking System
This question tests your ability to design a distributed system that manages transactional integrity, high concurrency during bookings, and efficient searching for room availability.
System DesignOnsiteConcurrencyDatabase ModelingDistributed Systems - RipplingMediumSoftware EngineerDesign a Hotel Search and Reservation System
Design an end-to-end hotel search and booking platform balancing high-throughput search with strictly consistent, transactional room inventory management across continuous date ranges.
System DesignOnsitesystem-designdistributed-systemsconcurrency
Pinterest
Plaid
Ramp
Reddit
Remitly
Retell AI
Rippling