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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 331–360 of 721 results
- LinkedInMediumSoftware EngineerScale a NoSQL Key–Value Store to One Million QPS
Design a distributed, highly available NoSQL key-value store capable of serving 1M QPS across 50 million key-value pairs with low p99 latency.
System DesignOnsitesystem-designnosqldistributed-systems - Luma AIMediumSoftware EngineerBuild Collaborative Document Editing Shared by People and AI Agents
A take-home asks you to build collaborative document editing in which people and AI agents edit the same document, then defend its scaling limits and add approval, audit history and selective revert for agent edits. Tests concurrency control, real-time sync, anchoring slow agent edits, attribution, and prototype scoping.
System DesignOnsite - Luma AIMediumSoftware EngineerBuild a Scalable Text-to-Speech Service Prototype, Then Defend and Extend It
An 8 to 12 hour take-home asks you to build a scalable text-to-speech service with AI coding agents, then defend its trade-offs and scaling limits in a product review and plan a new customer requirement. Tests 0-to-1 scoping, streaming and batch synthesis design, capacity reasoning, and estimation and roadmap skills.
System DesignOnsite - LyftMediumSoftware EngineerDesign One-to-One Messaging Across Multiple Devices
Tests the ability to architect a real-time, one-to-one messaging system supporting multi-device synchronization, push notifications, idempotent message delivery, and reliable cursor-based history pagination.
System DesignOnsitesystem-designdistributed-systemsmessaging - LyftMediumSoftware EngineerDesign a Distributed Web Crawler
Design a distributed web crawler that starts from seed URLs and scales across roughly 1,000 heterogeneous worker devices. The question covers canonical URL identity and crawl scope, a durable partitioned frontier with atomic deduplication, host-level politeness and robots handling, lease-based coordination with at-least-once delivery and idempotent effects, fetch/parse/storage schemas, near-duplicate detection, recrawl and backpressure, capacity estimation, safety controls, and the enqueue/status/results API. A common Lyft software engineer onsite system design question testing distributed-systems judgment, correctness under retries, and operational thinking.
System DesignOnsite - LyftHardSoftware EngineerDesign a Donation Platform
A Lyft onsite system design question: design an online donation platform that processes one-time and recurring donations through an external payment provider while guaranteeing no lost, duplicated, or wrong-amount charges. It tests payment-flow correctness, idempotency, append-only ledgers, reconciliation, data modeling, consistency tradeoffs, and scaling for donation spikes.
System DesignOnsite - LyftEasySoftware EngineerDesign a Fault-Tolerant Wikipedia Archiver
Design a fault-tolerant system that archives Wikipedia and keeps versioned content current using one reliable coordinator, many unreliable untrusted workers, and durable blob storage. Cover policy-aware discovery, large-frontier deduplication, task assignment, result validation, safe publication, failure recovery, and recrawling.
System DesignOnsite - LyftMediumSoftware EngineerDesign a One-to-One Chat Service
Design a durable one-to-one chat service with conversation ordering, idempotent sends, offline replay, and secure multi-device delivery.
System DesignOnsite - LyftMediumSoftware EngineerDesign a Wiki Crawler That Keeps Every Stored Page at Most Five Days Stale
A system design question about crawling and storing all the content of a wiki while keeping every stored page no more than five days stale. It tests capacity estimates, the crawl frontier and scheduling, change detection, storage of page versions, politeness limits, failure recovery, and monitoring of freshness.
System DesignOnsite - LyftHardSoftware EngineerDesign a scalable real-time chat system
This question evaluates skills in designing scalable real-time distributed systems, covering API design, message ordering and idempotency, fan-out strategies, storage tiers, indexing, sharding and replication, consistency vs.
System DesignOnsite - LyftHardSoftware EngineerDesign web crawler for 1000 devices
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 web crawler for 1000 devices states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
System DesignOnsite - MathWorksMediumSoftware EngineerDesign a Scalable Product Authentication Platform
Design authentication infrastructure for browser and API clients using email and password today with room for external identity providers later. Cover secure credentials, session lifecycle, abuse resistance, recovery, database choices, trust boundaries, and a path to tenfold traffic.
System DesignOnsite - MercorMediumMachine Learning EngineerDesign a DAG Pipeline Runner for Data-Labeling Jobs
Design a multi-tenant service that runs user-defined DAGs of automated steps (pre-processing, model pre-labeling, QA checks, exports), tracks every run, and survives crashes. Tests data modeling, separating the scheduler from workers, durable state, retries and idempotency, tenant fairness and observability.
System DesignOnsiteworkflow-orchestrationdistributed-systemsstate-machines - MercorMediumMachine Learning EngineerDesign a High-Demand Event Ticket Marketplace
Design an event ticketing platform capable of handling flash-sale spikes without overselling, featuring transactional seat holds, idempotent payment processing, and virtual queueing.
System DesignOnsitesystem-designdistributed-systemsconcurrency - MercorMediumMachine Learning EngineerDesign a workflow orchestration system that runs multi-step jobs reliably
A system design question asking you to build a workflow system where users define multi-step workflows with dependencies, start runs, and track progress. It tests data modeling, orchestration and worker architecture, durable state, retries and idempotency, fairness between tenants, scaling and observability.
System DesignOnsite - MetaMediumSoftware EngineerDesign 24-Hour Ephemeral Stories for a Photo and Video Sharing App
A system design question on ephemeral stories that followers can view for 24 hours before they disappear, covering media upload, the tray of accounts with unwatched stories, playback, and viewer tracking. It tests expiry semantics, fan-out for popular authors, watched-state storage, and media delivery.
System DesignOnsite - MetaHardSoftware EngineerDesign Boolean Search for Status Posts
This problem tests the ability to design an inverted index system that supports complex logical queries, high-concurrency updates, and consistent pagination over a distributed dataset.
System DesignOnsiteInverted IndexSearchDistributed Systems - MetaMediumSoftware EngineerDesign Boolean Search over User Status Posts
This problem tests the design of a scalable inverted index system capable of handling boolean queries (AND/OR/NOT) over a high-throughput stream of user status updates.
System DesignOnsiteInverted IndexBoolean SearchConcurrency - MetaMediumSoftware EngineerDesign Real-Time Auctions for Social Posts
This question evaluates skills in designing scalable, low-latency real-time systems, including distributed architecture, concurrency control and ordering, data modeling, API design, and fault-tolerance for high-contention auction workloads.
System DesignOnsite - MetaHardSoftware EngineerDesign Ride Requests, Driver Matching, and Trip State
Design a high-scale real-time ride-hailing dispatch and trip lifecycle backend. The problem tests geospatial indexing, high-throughput location ingestion, concurrent driver assignment without double-booking, and idempotent distributed state management.
System DesignOnsiteDistributed SystemsGeospatialConcurrency - MetaHardSoftware EngineerDesign a Dropbox-like file storage and sync service
Design a Dropbox-like file storage and sync service 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.
System DesignOnsite - MetaMediumSoftware EngineerDesign a Messenger-Style Chat Backend Without WebSockets or Persistent Connections
Design a Messenger-style chat backend for one-to-one conversations without WebSockets or other persistent connections, using only request/response web APIs. Tests message ordering, idempotent sends, cursor-based sync, cheap polling, push wake-ups, multi-device delivery and failure handling at very large scale.
System DesignOnsite - MetaMediumSoftware EngineerDesign a Notification System That Delivers Events to Users at Scale
A system design question on a notification platform that takes events from many product services and delivers them to users through push and in-app channels. It tests ingestion contracts, preference checks, grouping and rate limiting, priority isolation, third-party push delivery, and deduplication under retries.
System DesignOnsite - MetaMediumSoftware EngineerDesign a People-You-May-Know Friend Recommendation System
A system design question on recommending people a user may know on a large social network, from candidate generation through ranking and serving. It tests graph-based candidate sourcing, batch versus real-time freshness, ranking signals and labels, filtering, privacy, cold start, and evaluation.
System DesignOnsite - MetaMediumSoftware EngineerDesign a Ranked Home News Feed for a Large Social Network
A system design question on building the home news feed of a large social network: publishing posts and serving each user a ranked, paginated feed of posts from the accounts they follow. It tests fan-out strategy, accounts with huge follower counts, ranking under a latency budget, and correctness for deletes and privacy.
System DesignOnsite - MetaMediumSoftware EngineerDesign a Real-Time Chat Service for One-to-One and Group Messaging
A system design question on a real-time chat service with one-to-one and group conversations, instant delivery to online users, offline catch-up, and history across devices. It tests connection routing, per-conversation ordering, idempotent sends, message storage, group fan-out, and read receipts.
System DesignOnsite - MetaMediumSecurity EngineerDesign a Real-Time Collaborative Coding Interview Pad, Then Threat-Model It
A two-phase security engineering design prompt from Meta: design a browser-based collaborative coding pad with real-time co-editing, code execution and session playback, then threat-model your own architecture. It tests concurrent editing, sandboxing untrusted code, access control, tenant isolation and risk prioritization.
System DesignOnsite - MetaMediumSoftware EngineerDesign a Real-Time Trending Hashtags System
This question evaluates a candidate's ability to design a large-scale, real-time data processing system that continuously scores and ranks trending content under strict freshness constraints. It tests system design skills including stream processing, time-decayed scoring, and handling high write throughput at scale. This type of question is commonly used to assess architectural thinking for systems balancing timeliness, popularity, and novelty signals.
System DesignOnsite - MetaMediumSoftware EngineerDesign a Reliable Notification System
Design an enterprise-scale notification platform supporting multi-channel delivery, recipient fanout, preference filtering, and resilient at-least-once delivery guarantees.
System DesignOnsiteDistributed SystemsMessage QueuesScalability - MetaMediumSoftware EngineerDesign a Top-K trending items service
This question tests the ability to design a high-throughput, distributed system that maintains a real-time ranking of the most popular items across a massive global user base.
System DesignOnsiteDistributed SystemsData StreamsCaching
LinkedIn
Luma AI
Lyft
MathWorks
Mercor
Meta