| 1 | telemetry ingestion naming variantsAnthropic 1Design a telemetry system; follow-up: if previously deployed clients used different naming variants for the same telemetry_name, how should … | OpenTelemetry Telemetry SchemasDesign a Metrics Monitoring Platform like DatadogVersioned telemetry schemas, server-side name translation |
| 1 | flawed design doc reviewAnthropic 1System design: review and improve a design doc that has problems in it | Refactoring English: How to write an effective design doc / get meaningful feedbackDesign Docs at GoogleCrafting Engineering StrategyFinding and prioritising flaws in a design doc |
| 1 | 1:1 messaging 100M DAUAnthropic 1Design a one-to-one text-messaging web app at 100M DAU that keeps messages for offline recipients; follow-ups: DB load at this scale, findin… | Design a Messaging App Like WhatsAppHow Discord Stores Trillions of MessagesDesigning Data-Intensive Applications, 2nd Edition100M DAU load, chat-ID lookup, lifecycle, lost/out-of-order messages |
| 1 | 1:1 chat systemAnthropic 1Design a 1-on-1 chat system (no groups/channels): offline push, presence, session storage, then Kafka vs Redis and Kafka internals | Design a Messaging App Like WhatsAppKafka Deep DiveReal-time Updates patternOffline push, presence, sessions, Kafka vs Redis pub/sub |
| 1 | real-time chess serviceOpenAI 1Design a chess game: tracking a user's remaining time, recovery after a client fails | Design an Online Chess PlatformDurable Objects: Easy, Fast, Correct — Choose threeServer-side clocks, game-state recovery after client failure |
| 1 | command dispatch + telemetry reconciliationOpenAI 1Design a power-grid dispatch center sending commands to devices by region (e.g. cut all Northeast air conditioners' usage by 20%) over unrel… | AWS IoT Device Shadow serviceThe Dataflow ModelDesired vs reported state, late telemetry reconciliation, next-round adjustment |
| 1 | fullstack app designOpenAI 1Fullstack system design with frontend focus from a 2-3 page doc with requirements, screenshot and GIF demo | Front End System Design PlaybookFrontend-focused system design from a product spec |
| 1 | IoT logging late metricsOpenAI 1Design an IoT log platform: many devices collect logs online/offline and batch-upload when online; platform can request devices record certa… | The Dataflow ModelDesign an Ad Click AggregatorAWS IoT Device Shadow serviceLate-arriving logs, watermarks, per-type metrics, device log requests |
| 1 | real-time electricity monitoringOpenAI 1Design a system to monitor electricity use of devices in real time and adjust usage strategies based on consumption | Time Series DatabasesMonarch: Google's Planet-Scale In-Memory Time Series DatabaseAWS IoT Device Shadow serviceReal-time device metrics, TSDB storage, control feedback |
| 1 | devbox serviceOpenAI 1Design a devbox (on-demand remote development environment) service | We're leaving KubernetesFirecracker: Lightweight Virtualization for Serverless ApplicationsOn-demand devbox lifecycle, storage, isolation |
| 1 | dedup photo storageOpenAI 1Extra SD: design a system where users upload, download and delete photos, keeping only one copy when content SHA256 matches an existing phot… | Design a File Storage Service Like DropboxFinding a Needle in Haystack: Facebook's Photo StorageContent-hash dedup, reference counting, blob storage |
| 1 | online devboxOpenAI 1Design an online devbox | We're leaving KubernetesgVisor documentationOnline devbox: environments, sandboxing, persistence |
| 1 | metrics monitoringOpenAI 1Metrics monitoring system design variation, going deep on 1-2 areas | Design a Metrics Monitoring Platform like DatadogMonarch: Google's Planet-Scale In-Memory Time Series DatabaseGorilla: A Fast, Scalable, In-Memory Time Series DatabaseMetrics pipeline; deep dives on storage and aggregation |
| 1 | content-addressed photo storageOpenAI 1Design a photo-storage service (upload/view/delete) with SHA-256 hashing: object storage, metadata, handling duplicate hashes, upload consis… | Design a File Storage Service Like DropboxFinding a Needle in Haystack: Facebook's Photo StorageSHA-256 addressing, object storage, metadata, duplicate handling |
| 1 | payment holds/charges/batchesOpenAI 1Design a payment processor: merchant hold request forwarded to upstream payment network for approval/rejection, later separate charge, charg… | Stripe's payments APIs: The first 10 yearsLedger: Stripe's system for tracking and validating money movementDesign a Payment System like StripeHolds via upstream network, captures, batched settlement |
| 1 | multiplayer typing raceOpenAI 1Design a typing race game for 2-8 players: generated passage, first to finish wins, 1-second freeze on a typo; cooldown/unfreeze mechanism, … | Durable Objects: Easy, Fast, Correct — Choose threeWhat Every Programmer Needs To Know About Game NetworkingReal-time Updates patternRoom actor, freeze timers, latency compensation, matchmaking |
| 1 | cloud IDE sandboxOpenAI 1Design a cloud IDE sandbox, including what happens inside the VM when the sandbox executes a user's program | gVisor documentationFirecracker: Lightweight Virtualization for Serverless ApplicationsBerkeley CS 162 Operating Systems and Systems ProgrammingSyscall interception and VM internals when running user programs |
| 1 | design SteamOpenAI 1Design Steam (digital game store and distribution platform) | Classic problem breakdowns: YouTube, Post Search, Yelp, News Feed, Web CrawlerDesign a File Storage Service Like DropboxGame distribution via CDN and chunked downloads, store catalog |
| 1 | payment authorization + settlementOpenAI 1Design a payment system: transactions approved/denied via an external payment service, approved amounts held, daily batch processing, ~10,00… | Stripe's payments APIs: The first 10 yearsLedger: Stripe's system for tracking and validating money movementSpanner: Google's Globally-Distributed DatabaseAuthorization, holds, settlement, ledger consistency |
| 1 | trivia battle royaleOpenAI 1Design a real-time trivia battle royale platform: dozens to ~100 players per room, questions released round by round, each round eliminates … | Durable Objects: Easy, Fast, Correct — Choose threeDesign Facebook's Live Comments SystemWhat Every Programmer Needs To Know About Game NetworkingPer-room authority, round timing, spectator fan-out |
| 1 | rate limiterOpenAI 1System design: rate limiting | Design a Distributed Rate LimiterSystem Design Interview – An Insider's Guide, Vols 1–2Token bucket vs sliding window, distributed counters |
| 1 | eventual consistencyOpenAI 1Phone screen system design about eventual-consistency guarantees | Consistency ModelsDynamo: Amazon's Highly Available Key-value StoreDesigning Data-Intensive Applications, 2nd EditionConsistency models, quorums, conflict resolution |
| 1 | OS and backend conceptsxAI 1Phone screen: OS conceptual questions and backend topics | Berkeley CS 162 Operating Systems and Systems ProgrammingStanford CS 144 Introduction to Computer NetworkingOS processes, memory, I/O; networking fundamentals |
| 1 | system design screenxAI 1Phone screen: system design discussion (onsite would have been 2 system design interviews) | System Design in a HurryGeneral screen: delivery framework and core concepts |
| 1 | Slack at scaleOpenAI 1Design Slack; what breaks at 100x or 1000x scale, and how do your assumptions hold up under much larger usage? | Real-time MessagingHow Discord Stores Trillions of MessagesScaling PostgreSQL to power 800 million ChatGPT usersWhat breaks at 100x: hot channels, DB load, fan-out |
| 1 | video streaming platformOpenAI 1Design a streaming platform: handling different frame rates and users worldwide; what changes at 10x, 100x, 1000x usage. | Classic problem breakdowns: YouTube, Post Search, Yelp, News Feed, Web CrawlerYouTube breakdown: transcoding, adaptive bitrate, CDN, global users |
| 1 | image processing serviceAnthropic 1Design an image processor: single processor then multiple; APIs for submit, check status, cancel; concurrency, producer-consumer, thread saf… | Managing Long Running Tasks patternDesign a Distributed Job Scheduler Like AirflowSubmit/status/cancel APIs, worker pools, producer-consumer concurrency |
| 1 | prompt sharing productAnthropic 1Design a prompt-sharing system: user flows, database schema, sharing mechanics, scaling for viral growth | Design a Collaborative Document Editor Like Google DocsDesign ChatGPTClassic problem breakdowns: YouTube, Post Search, Yelp, News Feed, Web CrawlerSharing model, schema, viral read scaling and caching |
| 1 | collaborative prompt playgroundAnthropic 1 · 1 staff+Design a Collaborative Prompt Playground: create, edit, test and collaborate on prompts (storage, real-time collaboration, versioning, execu… | How Figma's multiplayer technology worksDesign a Collaborative Document Editor Like Google DocsDistributed Systems lecture series (Cambridge)Real-time collaboration, CRDT/LWW sync, prompt storage |
| 1 | scale event-log processingxAI 1Part 2 of the Spaces problem: system design discussion on scaling the active-time computation | The Dataflow ModelKafka Deep DiveMapReduce: Simplified Data Processing on Large ClustersScaling event-log aggregation: stream windows vs batch |
| 1 | payments hold and settleOpenAI 1Design a payments pipeline that forwards to a payment processor, holds funds, then batch-settles daily | Ledger: Stripe's system for tracking and validating money movementMulti-step Processes patternStripe's payments APIs: The first 10 yearsHold, forward to processor, daily batch settlement and reconciliation |
| 1 | GitHub ActionsOpenAI 1Design a multi-tenant CI/CD workflow system for many orgs / design GitHub Actions from scratch | How GitHub uses GitHub Actions and Actions larger runners to build and test GitHub.comDesign a Distributed Job Scheduler Like AirflowAvoiding insurmountable queue backlogsMulti-org workflow engine, runner isolation, fair scheduling |
| 1 | online chess real-timeOpenAI 1Design online chess | Design an Online Chess PlatformOnline chess end to end |
| 1 | team messagingOpenAI 1Design a Slack-like team messaging service | Real-time MessagingDesign a Messaging App Like WhatsAppTeam messaging channels, fan-out, storage |
| 1 | video streamingOpenAI 1Design Netflix | Classic problem breakdowns: YouTube, Post Search, Yelp, News Feed, Web CrawlerVideo streaming: encoding pipeline, CDN, metadata |
| 1 | sandboxed cloud IDEOpenAI 1Design a multi-tenant, isolated cloud IDE / code execution environment (like Google Colab or Replit) from scratch | Firecracker: Lightweight Virtualization for Serverless ApplicationsgVisor documentationWe're leaving KubernetesMulti-tenant isolation, microVMs, notebook/IDE lifecycle |
| 1 | 1:1 chat at scaleAnthropic 1 · 1 staff+Design a 1:1 chat system; interviewer kept pushing on scale (candidate suspected a Pub/Sub channel design was expected). | Design a Messaging App Like WhatsAppHow Discord Stores Trillions of MessagesReal-time MessagingScaling beyond single pub/sub: partitioned routing, storage |
| 1 | livestream chatAnthropic 1 · 1 staff+Design a Livestream Chat Service. | Design Facebook's Live Comments SystemHigh fan-out livestream comments |
| 1 | CI job execution platformOpenAI 1 · 1 staff+Design GitHub Actions. | How GitHub uses GitHub Actions and Actions larger runners to build and test GitHub.comDesign a Distributed Job Scheduler Like AirflowGitHub Actions dispatch and execution |
| 1 | time-boxed chat MVPOpenAI 1 · 1 staff+Design a Slack-like service with a two-week MVP deadline. | Crafting Engineering StrategyReal-time MessagingMVP cut list, then scaling the delivery path |
| 1 | Claude chat serviceAnthropic 1Design the Claude chat service. | Design ChatGPTScaling PostgreSQL to power 800 million ChatGPT usersLLM chat service: streaming, conversations, capacity |
| 1 | distributed search 1B docsAnthropic 1Design a distributed search system for 1 billion documents at 1 million QPS. | Classic problem breakdowns: YouTube, Post Search, Yelp, News Feed, Web CrawlerBigtable: A Distributed Storage System for Structured DataPost Search and Elasticsearch: sharded inverted index, replicas, QPS |
| 1 | webhook delivery systemOpenAI 1Design and build a webhook delivery system that reliably delivers events to customer-registered URLs. | Webhook scalability: how to scale webhook deliveryDesigning robust and predictable APIs with idempotencyReliable delivery to customer URLs with retries and dedup |
| 1 | banking app designAnthropic 1Design a banking app | System Design Interview – An Insider's Guide, Vols 1–2Ledger: Stripe's system for tracking and validating money movementDigital wallet chapter, double-entry balances, transfers |
| 1 | design YelpOpenAI 1Design Yelp (pre-onsite system design screen, Excalidraw). | Classic problem breakdowns: YouTube, Post Search, Yelp, News Feed, Web CrawlerYelp breakdown and proximity-search deep dive |
| 1 | design FoursquareOpenAI 1Design Foursquare (pre-onsite system design screen, Excalidraw). | Classic problem breakdowns: YouTube, Post Search, Yelp, News Feed, Web CrawlerProximity search and check-ins, same as Yelp pattern |
| 1 | design TwitterOpenAI 1Design Twitter (pre-onsite system design screen, Excalidraw). | Classic problem breakdowns: YouTube, Post Search, Yelp, News Feed, Web CrawlerNews feed breakdown: fan-out on write vs read |
| 1 | notifications systemOpenAI 1Design a notifications system (pre-onsite system design screen, Excalidraw). | Design a Notification SystemNotification channels, preferences, retries, dedup |
| 1 | design then code alternativeOpenAI 1System design round where, after designing a solution, the candidate was asked to code up a new solution using a different method. | System Design in a HurryJordan has no life (system design YouTube)Practise alternative designs and trade-offs aloud |
| 1 | low-level system design E6+Meta MSL 3 · 3 staff+Design Redis | Design a Distributed Cache Like RedisKafka Deep DiveKafka: a Distributed Messaging System for Log ProcessingRedis internals and Kafka log design |
| 1 | AI-native design MermaidMeta MSL 1AI-native design interview: system design done in CoderPad using Mermaid Markdown diagrams with the authorized AI assistant available. | Mermaid diagram syntaxSystem Design in a HurryMermaid diagram syntax plus standard delivery framework |
| 1 | file cache systemAnthropic 1Design a file cache system. | Design a Distributed Cache Like RedisDatabase InternalsCache eviction, sharding, consistency, storage layout |
| 1 | web crawler designAnthropic 1Design a web crawler. | Classic problem breakdowns: YouTube, Post Search, Yelp, News Feed, Web CrawlerWeb crawler breakdown: frontier, politeness, dedup |
| 1 | design OpenAI PlaygroundOpenAI 1Design the OpenAI Playground. | Design ChatGPTClaude API: rate limits and API overviewPlayground product backed by a model API |
| 1 | task manager with subtasksxAI 1Design a task management system with tasks broken into sub-tasks. | Multi-step Processes patternDesign a Distributed Job Scheduler Like AirflowParent/child tasks, workflow state, retries |
| 1 | file upload for AI chat appxAI 1Design a file upload feature for an AI chat application. | Design a File Storage Service Like DropboxPresigned chunked uploads, large-blob pattern, processing |
| 1 | rate limiter designxAI 1Design a rate limiter. | Design a Distributed Rate LimiterDistributed rate limiter design |
| 1 | design GitHubOpenAI 1Design a system like GitHub and explain how a user interacts with it. | Stretching SpokesHow GitHub uses GitHub Actions and Actions larger runners to build and test GitHub.comGit repository replication, CI integration, user flows |
| 1 | architecture overload protectionAnthropic 1Walk through the end-to-end flow of this architecture, then explain how it handles overload. | Google SRE books (Site Reliability Engineering; The Site Reliability Workbook)Avoiding insurmountable queue backlogsFixing retries with token buckets and circuit breakersLoad shedding, cascading failure, retry budgets, backpressure |
| 1 | malware scanner dashboardxAI 1Design a malware scanner reporting dashboard. | Design an Ad Click AggregatorVirusTotal: How it worksScan-result aggregation pipeline and reporting store |
| 1 | payment system coffee shopOpenAI 1Payment System / Coffee-Shop Ordering: Design the in-store ordering and card-payment system for a coffee chain. | Design a Payment System like StripeStripe's payments APIs: The first 10 yearsCard authorization flow and order/payment state |
| 1 | analytics dashboard AI chatAnthropic 1Design an analytics dashboard for an AI chat app | Design an Ad Click AggregatorTime Series DatabasesThe Dataflow ModelEvent aggregation, OLAP storage, late events |
| 1 | livestream chat serviceAnthropic 1 · 1 staff+Design a Livestream Chat Service | Design Facebook's Live Comments SystemLivestream chat fan-out |
| 1 | debugging distributed systemsxAI 1How do you approach debugging complex distributed systems? | Google SRE books (Site Reliability Engineering; The Site Reliability Workbook)Dapper, a Large-Scale Distributed Systems Tracing InfrastructureA postmortem of three recent issuesTroubleshooting method, tracing, real incident reasoning |