# System Design Interview Guides Source: https://www.techinterview.org/system-design-interview-guides/ Updated: 2026-07-17 · techinterview.org system design System Design Interview GuidesThe system-design questions that actually come up, each worked end to end — one canonical walkthrough per topic. Start with the framework, then drill into what you are prepping for. **50** guidesRequest path: client, load balancer, service, cache and databaseclientLBsvcsvccachedbp99 < 200msfan-out, cache-aside, replica reads[**New to system design? Start with the step-by-step interview framework →**](https://www.techinterview.org/post/3233474136/system-design-interview-framework-step-by-step-requirements-estimation-high-level-design-deep-dive-tradeoffs/) ## Feeds, social & content 3 guides [**Design Twitter / a news feed**Twitter/X builds the home timeline mostly with fanout-on-write: when you post, the tweet is pushed…](https://www.techinterview.org/post/3233474168/system-design-twitter-news-feed-timeline-fanout-on-write-fanout-on-read-celebrity-problem-ranking-caching/)[**Design Instagram**Designing a photo-sharing platform like Instagram tests your ability to handle media-heavy workloads, social graph…](https://www.techinterview.org/post/3233474174/system-design-instagram-photo-sharing-image-upload-news-feed-stories-explore-page-cdn-image-processing-social-graph/)[**Design a social graph**A social graph stores relationships between users (friendships, follows, connections) and enables graph queries: friends…](https://www.techinterview.org/post/3233461036/system-design-social-graph/) ## Real-time & collaboration 5 guides [**Design collaborative editing (Google Docs)**Design it around a concurrency-control algorithm — Operational Transformation (OT) or Conflict-free Replicated Data Types…](https://www.techinterview.org/post/3233460997/system-design-collaborative-editing/)[**Design Figma**Figma is a browser-based collaborative design tool used by millions of designers, serving as a…](https://www.techinterview.org/post/3233474360/system-design-design-figma-collaborative-design-tool-real-time-multiplayer-vector-rendering-component-library-version-control/)[**Design Notion**Notion is a collaborative workspace that combines documents, databases, wikis, and project management in a…](https://www.techinterview.org/post/3233474362/system-design-design-notion-collaborative-workspace-blocks-database-real-time-editing-permissions-api-integrations/)[**Design Discord**Design Discord as a real-time, event-driven system: persistent WebSocket "gateway" connections fan out text messages,…](https://www.techinterview.org/post/3233474372/system-design-design-discord-voice-text-channels-server-architecture-webrtc-permissions-bots-real-time-presence/)[**Design a chat app (WhatsApp / Messenger)**Designing a chat application like WhatsApp or Facebook Messenger is a classic system design question…](https://www.techinterview.org/post/3233474166/system-design-chat-application-whatsapp-messenger-real-time-messaging-websocket-message-delivery-group-chat-end-to-end-encryption/) ## Marketplaces & commerce 7 guides [**Design a ticketing system (Ticketmaster)**Design a Ticketmaster-style system around three hard problems: absorbing huge read and write spikes the…](https://www.techinterview.org/post/3233460847/system-design-ticketing/)[**Design inventory management**An inventory management system tracks the quantity of products across one or more warehouses, coordinates…](https://www.techinterview.org/post/3233465583/system-design-inventory-management/)[**Design a flash sale**A flash sale offers a limited quantity of items at a steep discount for a…](https://www.techinterview.org/post/3233465613/system-design-flash-sale/)[**Design ride-sharing (Uber / Lyft)**Designing a ride-sharing application like Uber or Lyft is one of the most comprehensive system…](https://www.techinterview.org/post/3233474162/system-design-ride-sharing-uber-lyft-matching-algorithm-eta-calculation-surge-pricing-driver-location-tracking/)[**Design food delivery (DoorDash)**Food delivery is a three-sided marketplace connecting customers, restaurants, and delivery drivers — more complex…](https://www.techinterview.org/post/3233460523/system-design-food-delivery/)[**Design Splitwise**Splitwise tracks shared expenses among friends, roommates, and travel groups -- helping millions of users…](https://www.techinterview.org/post/3233474468/system-design-design-splitwise-expense-sharing-debt-simplification-group-balances-payment-integration-currency-conversion/)[**Design a hotel-reservation system**A hotel reservation system manages room inventory, bookings, availability search, and payments for hotels. Examples:…](https://www.techinterview.org/post/3233462959/system-design-hotel-reservation-system/) ## Payments & fintech 3 guides [**Design a payment system (Stripe)**Payment systems are among the most critical and complex components in software engineering. A bug…](https://www.techinterview.org/post/3233474171/system-design-payment-system-stripe-idempotency-double-charge-prevention-ledger-reconciliation-pci-compliance-webhooks/)[**Design an electronic trading platform**Electronic trading platforms process millions of orders per second with microsecond-level latency. Designing a trading…](https://www.techinterview.org/post/3233474476/system-design-design-electronic-trading-platform-order-book-matching-engine-market-data-feed-low-latency-colocation/)[**Design a real-time bidding system**The global programmatic advertising market is $500B. Every time a web page loads, a real-time…](https://www.techinterview.org/post/3233460859/system-design-real-time-bidding/) ## Storage & databases 4 guides [**Design a key-value store (DynamoDB)**Designing a distributed key-value store is a foundational system design question that tests your understanding…](https://www.techinterview.org/post/3233474180/system-design-key-value-store-dynamodb-lsm-tree-sstable-memtable-compaction-bloom-filter-consistent-hashing-wal/)[**Design database sharding**A single database server has limits: storage capacity (~tens of terabytes), write throughput (~tens of…](https://www.techinterview.org/post/3233464915/system-design-database-sharding/)[**Design database replication**Database replication copies data across multiple servers to achieve high availability, fault tolerance, and read…](https://www.techinterview.org/post/3233474156/system-design-database-replication-primary-replica-synchronous-asynchronous-multi-master-read-replicas-replication-lag/)[**Design a time-series database**Time-series databases are optimized for storing and querying timestamped data: application metrics, IoT sensor readings,…](https://www.techinterview.org/post/3233474179/system-design-time-series-database-influxdb-prometheus-timescaledb-iot-metrics-storage-compression-downsampling-retention/) ## Distributed-systems fundamentals 6 guides [**Distributed consensus (Raft / Paxos)**Distributed consensus is the foundation that makes distributed systems reliable. Every replicated database, every coordination…](https://www.techinterview.org/post/3233474129/system-design-distributed-consensus-raft-paxos-leader-election-log-replication-split-brain-quorum-linearizability/)[**Consistent hashing**Consistent hashing is a distributed hashing scheme that minimises key remapping when nodes are added…](https://www.techinterview.org/post/3233464248/system-design-consistent-hashing/)[**Distributed locking**A mutex works within a single process. A database row lock works within a single…](https://www.techinterview.org/post/3233464798/system-design-distributed-locking/)[**Distributed transactions (saga)**In a monolith with a single database, ACID transactions guarantee atomicity: either all operations succeed…](https://www.techinterview.org/post/3233464776/system-design-distributed-transaction/)[**The CAP theorem**The CAP theorem is the most cited theorem in distributed systems -- and the most…](https://www.techinterview.org/post/3233474185/system-design-cap-theorem-deep-dive-consistency-availability-partition-tolerance-pacelc-eventual-consistency-linearizability/)[**Multi-region architecture**Multi-region architecture distributes your application across multiple geographic regions to achieve low latency for global…](https://www.techinterview.org/post/3233474154/system-design-multi-region-architecture-active-active-active-passive-data-replication-failover-disaster-recovery-rpo-rto/) ## Infrastructure & platform 11 guides [**Design a rate limiter**Rate limiting protects APIs from abuse, prevents resource exhaustion, and ensures fair usage across clients.…](https://www.techinterview.org/post/3233474159/system-design-rate-limiter-token-bucket-sliding-window-leaky-bucket-distributed-rate-limiting-api-gateway/)[**Design a distributed task scheduler**A distributed task scheduler executes jobs at specified times or intervals across a fleet of…](https://www.techinterview.org/post/3233474183/system-design-distributed-task-scheduler-cron-job-delayed-execution-priority-queue-exactly-once-celery-temporal-airflow/)[**Design a load balancer**Load balancers distribute incoming traffic across multiple servers to ensure no single server becomes a…](https://www.techinterview.org/post/3233474140/system-design-load-balancer-architecture-l4-l7-nginx-haproxy-round-robin-least-connections-health-checks-ssl-termination/)[**Design a distributed cache (Redis)**Caching is the single most impactful performance optimization in distributed systems. A well-designed caching layer…](https://www.techinterview.org/post/3233474139/system-design-distributed-caching-redis-memcached-cache-aside-write-through-eviction-policies-cache-stampede-consistency/)[**Design a CDN**What Is a CDN? A Content Delivery Network is a globally distributed network of servers…](https://www.techinterview.org/post/3233460559/system-design-cdn/)[**Design an API gateway**An API gateway is the single entry point for all client requests in a microservices…](https://www.techinterview.org/post/3233474191/system-design-api-gateway-architecture-kong-aws-api-gateway-envoy-authentication-rate-limiting-request-routing-transformation/)[**Design a message queue (Kafka)**Apache Kafka processes trillions of events per day at companies like LinkedIn, Netflix, Uber, and…](https://www.techinterview.org/post/3233474488/system-design-design-kafka-distributed-event-streaming-platform-partitions-consumer-groups-exactly-once-compaction-connect/)[**Design a web crawler**A web crawler systematically browses the internet to download web pages for indexing, archiving, or…](https://www.techinterview.org/post/3233474161/system-design-web-crawler-distributed-crawling-url-frontier-politeness-deduplication-robots-txt-pagerank-sitemap/)[**Design search autocomplete / typeahead**Search autocomplete (typeahead) suggests query completions as the user types, reducing keystrokes and guiding users…](https://www.techinterview.org/post/3233474192/system-design-search-autocomplete-typeahead-trie-elasticsearch-ranking-debouncing-personalization-trending-queries/)[**Design a logging system**A centralized logging system collects, indexes, and makes searchable the logs from hundreds or thousands…](https://www.techinterview.org/post/3233474195/system-design-logging-system-elk-stack-fluentd-structured-logging-log-aggregation-retention-cost-optimization-loki/)[**Design service discovery**In a microservices architecture, services must find and communicate with each other despite dynamic scaling,…](https://www.techinterview.org/post/3233474182/system-design-service-discovery-consul-dns-etcd-eureka-health-checking-load-balancing-service-mesh-kubernetes-service/) ## Media & scheduling 3 guides [**Design video conferencing (Zoom)**Designing a video conferencing system like Zoom or Google Meet is a complex system design…](https://www.techinterview.org/post/3233460400/system-design-video-conferencing/)[**Design video streaming (Netflix)**Netflix serves over 200 million subscribers across 190 countries, streaming billions of hours of video…](https://www.techinterview.org/post/3233474186/system-design-video-streaming-netflix-adaptive-bitrate-hls-dash-transcoding-cdn-recommendation-engine-microservices/)[**Design Google Calendar**Google Calendar manages billions of events for hundreds of millions of users with complex scheduling…](https://www.techinterview.org/post/3233474350/system-design-design-google-calendar-scheduling-recurring-events-reminders-timezone-free-busy-room-booking-sync/) ## ML & AI systems 5 guides [**Design a recommendation system**Why Recommendations Matter Netflix reports that 80% of content watched is discovered through recommendations. Spotify…](https://www.techinterview.org/post/3233460594/system-design-recommendation-system/)[**The ML system-design interview**ML system design interviews are distinct from algorithm interviews and from traditional system design interviews.…](https://www.techinterview.org/post/3233460469/machine-learning-system-design-interview/)[**Design an ML search-ranking system**Search ranking is one of the most technically demanding ML system design problems. It combines…](https://www.techinterview.org/post/3233460105/ml-system-design-build-a-search-ranking-system/)[**Design an AI knowledge base (RAG)**AI-powered knowledge bases (Notion AI, Confluence AI, Glean) answer questions by searching and synthesizing information…](https://www.techinterview.org/post/3233474487/system-design-design-notion-ai-knowledge-base-semantic-search-document-qa-embeddings-context-retrieval-prompt-management/)[**Design ML training infrastructure**Companies building AI products at scale — OpenAI, Google, Meta, Databricks, and any company serious…](https://www.techinterview.org/post/3233460883/system-design-ml-training-infrastructure/) ## Frontend system design 3 guides [**Frontend: a Figma-style collaborative editor**Figma's collaborative editor is the canonical frontend system design problem of the 2020s. The question…](https://www.techinterview.org/post/3233474948/frontend-system-design-figma-collaborative-editor/)[**Frontend: a Notion-style block editor**Notion's block-based editor is the second most-asked frontend system design question after Figma's collaborative editor.…](https://www.techinterview.org/post/3233474953/frontend-system-design-notion-block-editor/)[**Frontend: build the GitHub repo UI**"Design GitHub's repo page" is a senior+ frontend system-design prompt. The page combines a file…](https://www.techinterview.org/post/3233475400/frontend-system-design-build-github-repository-ui/)