System Design
Architecture and system design scenarios
Design a monitoring and alerting system for a microservices architecture running on Kubernetes. Consider metrics, logs, traces, and alerting.
Design a globally available URL shortener like TinyURL/Bitly. Cover API design, key generation, storage, redirects, analytics, abuse prevention, and scalability.
Design a globally distributed rate limiter for multi-region APIs supporting per-user, per-IP, and per-endpoint quotas.
Design a web/mobile chat system with 1:1 and group chats, typing indicators, presence, read receipts, and offline support.
Design a personalized news feed for a social network with billions of events per day. Cover write fan-out vs read fan-out, ranking, and cold start.
Design a secure cloud file storage and sync service with versioning, sharing, offline sync, and deduplication.
Design a service to send notifications via email, SMS, and push at scale with retries, templates, and user preferences.
Design real-time driver-rider matching and dispatch with surge pricing, ETA, live location, and fraud detection.
Design a video streaming platform supporting uploads, transcoding, adaptive bitrate streaming (ABR), DRM, and global delivery.
Design an autocomplete service that suggests queries as users type, with personalization and typo tolerance.
Design a pipeline to ingest, process, and query billions of events per day with second-level latency and exactly-once semantics.
Design a highly available checkout/cart system handling flash sales, inventory reservations, payments, and order confirmation.
Design a payment gateway supporting multiple processors, 3-D Secure, refunds, settlements, and PCI concerns.
Design a low-latency feature flag platform with targeting rules, audit logs, and mobile/edge delivery.
Design a federated GraphQL gateway that composes multiple subgraphs, with caching, authorization, and schema evolution.
Design a Google Docs–style collaborative editor with real-time edits, offline support, and conflict resolution.
Design a judge/sandbox to safely compile and run untrusted code in multiple languages with resource limits and scaling.
Design a SaaS platform with tenant isolation, noisy-neighbor controls, per-tenant config, and usage-based billing.
Design an ad event pipeline for impressions, clicks, and conversions with deduplication, fraud detection, and near-real-time reporting.
Design a “find my friends” style service with real-time location updates, privacy zones, and battery-friendly clients.
Design a reliable, horizontally scalable scheduler (distributed cron) that supports one-off and recurring jobs with retries and idempotency.
Design a multi-tenant API gateway that handles routing, auth, rate limiting, request/response transformations, canarying, and observability across regions.
Design a horizontally scalable time-series database for metrics with high-cardinality support, rollups, and retention policies.
Design an internet-scale crawler with deduplication, politeness, incremental updates, and a query-time search index.
Design a recommendations system (e.g., “people you may know” or product recs) with offline training, nearline updates, and real-time ranking.
Design a marketplace platform with listings, search, buyer/seller profiles, escrow-like payments, dispute resolution, and fraud prevention.
Design a concert/movie ticketing platform with seat maps, concurrent holds, payment timeouts, and scalper/bot mitigation.
Design a platform to ingest telemetry from millions of devices with intermittent connectivity, command/control, and fleet management.
Design an ML feature store that supports offline feature engineering and online low-latency serving with consistency guarantees.
Design a system for storing secrets and managing encryption keys with rotation, auditing, and fine-grained access control.
Design an experimentation platform supporting randomization, exposure logging, guardrails, sequential testing, and per-metric analysis at scale.
Design a distributed cache that supports eviction policies, consistency across nodes, replication, and client-side failover.
Design a blockchain ledger for financial transactions with consensus, immutability, and efficient query capabilities.
Design a distributed search engine like Elasticsearch that supports indexing, querying, replication, and relevance ranking.
Design a global CDN for static and dynamic content delivery, cache invalidation, SSL termination, and DDoS protection.
Design a HIPAA-compliant healthcare records platform with fine-grained access control, audit logs, and interoperability (HL7/FHIR).
Design an edtech platform with courses, video streaming, assessments, adaptive learning, and collaboration features.
Design a centralized logging system for microservices with ingestion, indexing, querying, and alerting at scale.
Design an email system that supports bulk sending, deliverability, spam compliance, tracking, and feedback loops.
Design a data warehouse platform supporting petabyte-scale storage, ELT/ETL pipelines, query federation, and cost controls.
Design a fraud detection system for online payments with real-time scoring, feature pipelines, and explainability.
Design a scalable video conferencing service like Zoom with low latency, adaptive quality, and security.
Design a multiplayer online gaming platform with matchmaking, anti-cheat, and real-time state sync.
Design a global publish/subscribe system with millions of subscribers, durable delivery, and filtering.
Design a platform to serve ML models at scale with versioning, monitoring, A/B testing, and GPU utilization.
Design a ticketing and support system with multi-channel intake, prioritization, and SLA tracking.
Design a recurring billing system with plan management, invoicing, dunning, and proration.
Design a food delivery platform with restaurant onboarding, live order tracking, payments, and surge pricing.
Design a database system that replicates across regions with low latency, conflict resolution, and disaster recovery.