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System Design interview questions

1311 System Design questions from 230 companies, with hints, runnable code and solution walkthroughs.

Questions1311

60 easy819 medium432 hard

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System Design interview questions by the numbers

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Katkat has 1,311 System Design interview questions from 230 companies; the most come from OpenAI (8%), Meta (5%) and Amazon (4%). By difficulty: 5% easy, 62% medium and 33% hard. The most common round is Onsite (55%). Frequent concepts include System Design, Distributed Systems, Scalability and Caching.

Companies (230)

Difficulty

  • Easy5% · 60
  • Medium62% · 819
  • Hard33% · 432

Interview rounds

  • Onsite55% · 721
  • Technical Screen39% · 517
  • Online Assessment3% · 38
  • Other2% · 21
  • HR Screen1% · 13

Roles

  • Software Engineer91% · 1189
  • Machine Learning Engineer2% · 31
  • Data Engineer2% · 26
  • Backend Engineer2% · 25
  • Frontend Engineer1% · 19

Frequent concepts

  • System Design31% · 400
  • Distributed Systems24% · 316
  • Scalability15% · 196
  • Caching7% · 95
  • Concurrency7% · 91
  • system-design6% · 83

Showing 151–180 of 1311 results

  • A cloud infrastructure design question asking what a cloud provider must build so customers can create, update and destroy its resources with Terraform. It tests mapping the Terraform resource lifecycle to provider APIs, handling long-running operations and their status, idempotent retries, and drift detection.

    AppleSoftware EngineerSystem DesignTechnical Screen
  • Define APIs and a core model for an authenticated election with one final ballot per voter and results hidden until close. The design discussion covers eligibility, deterministic timing, idempotent voting, concurrent submissions, recountable records, audit trails, and privacy boundaries.

    AppleSoftware EngineerSystem DesignTechnical Screen
  • This question evaluates the ability to design a scalable CI/CD and MLOps platform that integrates backend services, model-serving APIs, data and feature pipelines, Kubernetes-based deployments, artifact and model versioning, security, and observability.

    AppleMachine Learning EngineerSystem DesignOnsite
  • Design a scalable cloud photo storage and multi-device synchronization system supporting resilient media uploads, conflict-free sync, and bandwidth-efficient thumbnail and preview generation.

    AppleSoftware EngineerSystem DesignOnsite
  • This question tests the ability to design a distributed synchronization system that balances low-latency local updates with eventually consistent cross-device state, focusing on conflict resolution, bandwidth optimization, and offline-first availability.

    AppleSoftware EngineerSystem DesignOnsite
  • This question evaluates a candidate's ability to design disk-based inventory services under tight RAM constraints, focusing on data layout, indexing strategies, caching, write/read paths, conditional updates, concurrency control, and I/O-latency trade-offs.

    AppleSoftware EngineerSystem DesignTechnical Screen
  • This problem tests the ability to design an end-to-end data pipeline for high-throughput mobile app event logging, focusing on ingestion, transformation, and storage optimization.

    AppleData EngineerSystem DesignTechnical Screen
  • Tests the candidate's ability to design a high-throughput, distributed log collection and search platform, balancing ingestion backpressure, index cost, query latency, and tiered storage.

    AppleSoftware EngineerSystem DesignOnsite
  • This problem tests the ability to design a scalable, low-latency distributed rate-limiting service using the token bucket algorithm while balancing consistency and performance.

    AppleSoftware EngineerSystem DesignOnsite
  • Design an interpretable palindrome-resemblance score with explicit character handling, similarity features, weights, edge cases, and computational trade-offs.

    AppleAccessories Software QA EngineerSystem DesignOnsite
  • A system design question on reporting the top K most-visited URLs over a sliding time window. It tests requirement clarification, stream ingestion and windowed counting, merging per-partition top-K results correctly, serving precomputed rankings, and handling hot keys, late events and exact versus approximate counts.

    AppleSoftware EngineerSystem DesignOnsite
  • This question evaluates system design and machine learning engineering skills for building a multimodal Retrieval-Augmented Generation (RAG) assistant, covering competencies in data ingestion and preprocessing across modalities, indexing and retrieval strategies, embeddings and re-ranking, grounding/prompting with citations, and evaluation and failure-mode mitigation. It is commonly asked to gauge an engineer's ability to architect scalable, grounded QA pipelines that balance retrieval quality, latency, and cost; it sits in the System Design domain and tests both high-level architectural reasoning and practical implementation considerations.

    AppleMachine Learning EngineerSystem DesignTechnical Screen
  • This question tests your ability to design a resource-constrained embedded sensing subsystem, focusing on the trade-offs between energy efficiency, data latency, and algorithmic reliability in a wearable device.

    AppleSoftware EngineerSystem DesignOnsite
  • This question tests the ability to design a high-throughput event processing system for ad clicks and a scalable file synchronization service, focusing on data consistency, idempotency, and distributed storage patterns.

    AppleSoftware EngineerSystem DesignOnsite
  • This question tests the ability to design a high-throughput, fault-tolerant system for tracking ad clicks while ensuring exactly-once processing or deduplication at scale.

    AppleSoftware EngineerSystem DesignTechnical Screen
  • This question evaluates system design and engineering skills including data modeling, indexing, geospatial and full-text search, caching, replication and sharding for a high-scale reviews platform, together with key generation, storage layout, redirects, rate limiting and analytics for a URL-shortening service, probing the ability to balance scalability, consistency, availability, and operational complexity. It falls under the System Design / Distributed Systems / Databases domain and is commonly asked to assess architectural reasoning and trade-off analysis, testing both conceptual high-level design and practical implementation considerations such as performance, fault tolerance, and operational constraints.

    AppleSoftware EngineerSystem DesignOnsite
  • This System Design question evaluates proficiency in large-scale architecture, API and storage design, data modeling, scalability and consistency trade-offs, ingestion and indexing pipelines, CDN and caching strategies, and operational concerns such as reliability, observability, security, and multi-region deployments across video-sharing and marketplace catalog domains. It is commonly asked in technical interviews to test architectural judgment and trade-off reasoning, emphasizing high-level practical application and operational planning rather than low-level implementation details.

    AppleSoftware EngineerSystem DesignOnsite
  • Implement a robust REST API method evaluates requirements, scale assumptions, API/data design, architecture, trade-offs, failure modes, and rollout in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

    AppleSoftware EngineerSystem DesignTechnical Screen
  • This question evaluates a candidate's ability to design and plan a safe, compliant migration of a high-scale digital wallet from a monolithic architecture to microservices, covering service decomposition, data ownership, transactional consistency, security and key management, compliance, observability, and deployment strategies.

    AppleSoftware EngineerSystem DesignTechnical Screen
  • Tests object-oriented domain modeling, interval-overlap availability logic, and concurrency control strategies to prevent double bookings in a hotel reservation system.

    AppleSoftware EngineerSystem DesignOnsite
  • A staff-level screen question about an existing service whose normalized relational database serves slow reads: explain how you would change the data model and read path to cut read latency. Tests diagnosis of slow reads, trade-offs between read cost, write cost and data freshness, and safe rollout on a live system.

    AppleSoftware EngineerSystem DesignTechnical Screen
  • This question evaluates a candidate's competency in designing scalable, low-latency distributed services that combine algorithmic optimization and caching to handle massive request volumes for a numerical convergence operation.

    AppleSoftware EngineerSystem DesignTechnical Screen
  • Design an end-to-end ingestion, validation, and storage pipeline for high-frequency sensor telemetry from autonomous vehicle fleets. The focus is on handling raw versus derived data, schema modeling, fast time-range queries, and robust validation.

    Applied IntuitionSoftware EngineerSystem DesignTechnical Screen
  • This question evaluates competency in designing scalable, durable distributed job schedulers, covering multi-tenant architecture, queuing and metadata persistence, execution semantics, idempotency, retries/dead-lettering, failure handling, and observability.

    Applied IntuitionSoftware EngineerSystem DesignOnsite
  • Design a system that plays recorded vehicle log data back as a smooth, seekable 3D scene without downloading the whole log first. It tests chunked, time-indexed streaming, prefetching and caching around the playhead, aligning data streams of different rates, and handling heavy sensor data at scale.

    Applied IntuitionSoftware EngineerSystem DesignOnsite
  • This question assesses the ability to architect a high-throughput simulation system capable of retrieving, syncing, and replaying synchronized sensor data streams for autonomous vehicle testing.

    Applied IntuitionSoftware EngineerSystem DesignOnsite
  • Discuss productionizing event-timeout detector evaluates requirements, scale assumptions, API/data design, architecture, trade-offs, failure modes, and rollout in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

    Applied IntuitionSoftware EngineerSystem DesignTechnical Screen
  • This question evaluates the candidate's proficiency in end-to-end system design—covering requirements definition, architecture and component design, data modeling, scalability, trade-off analysis, and operational readiness—within the System Design domain for a software engineer role.

    Applied IntuitionSoftware EngineerSystem DesignTechnical Screen
  • This question evaluates system design and algorithmic reasoning for constrained spatio-temporal matching and routing, covering Manhattan-distance geometry, matching algorithms, API and data model design, and scalability/consistency considerations.

    ApplovinSoftware EngineerSystem DesignTechnical Screen
  • This question evaluates system-design skills for building real-time collaborative applications, covering data modeling, read/write paths, real-time synchronization, concurrent edits and reordering semantics, permission models, and consistency trade-offs within the System Design domain.

    AsanaSoftware EngineerSystem DesignOnsite

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