System design problems

Build a scalable URL shortening service that supports creation, redirection, caching, and analytics ingestion for a fast user experience.

Design a small semantic-search service that ingests documents, creates embeddings asynchronously, and returns tenant-isolated nearest-neighbor results.

Design a one-to-one chat system with authenticated connections, durable messages, online delivery, offline notifications, and replay after reconnect.

Design a typeahead service that returns popular, safe, and fresh query suggestions within a tight interactive latency budget.

Design a text-sharing service that creates immutable pastes, serves popular content quickly, expires data safely, and limits abusive public traffic.

Design a durable shopping cart that supports guest and signed-in users, fast item updates, price revalidation, and a safe handoff into checkout.

Design a media platform for uploading, processing, storing, and delivering photos to users with edge caching and metadata search.

Build a request rate limiting service that protects APIs from abuse and ensures fair access for clients.

Create a tracking system for orders, restaurant updates, and rider location streaming with live customer notifications.

Build an AI knowledge assistant that ingests documents, retrieves relevant context, and generates grounded answers for users.

Design a notification platform that fans out product events to push, email, or SMS channels with retries and user preferences.

Build a low-latency feature flag and experiment platform for SDK evaluation, rule management, audit history, and event ingestion.

Build a GraphQL API layer for commerce clients that aggregates catalog, inventory, pricing, recommendations, and order data while enforcing query safety.

Build a public developer API platform with WAF protection, authentication, quotas, request validation, partner dashboards, and backend aggregation.

Build a live sports scoreboard that ingests match events, computes state, and pushes low-latency updates to web and mobile clients.

Build a scheduled billing reconciliation system that imports provider reports, compares them to internal ledger records, and produces audited correction workflows.

Design a multi-device file synchronization service with resumable uploads, block deduplication, version history, change feeds, and conflict-safe offline recovery.

Design a ticket-booking platform that supports event discovery, realtime seat maps, short-lived holds, idempotent checkout, and fair admission during onsale spikes.

Design a polite distributed web crawler that schedules URLs, respects per-host limits, deduplicates content, stores crawl history, and feeds a searchable document index.

Design a real-time messaging system with presence, message delivery, persistence, and offline support for mobile users.

Build a search service that indexes large data sets, serves low-latency queries, and supports incremental refresh with caching.

Build a marketplace platform that supports browsing inventory, placing orders, and processing fulfillment asynchronously.

Build a video platform that supports upload, encoding, storage, search, and fast content delivery to viewers.

Design a social feed service that publishes posts, generates personalized timelines, and serves high-read traffic with caching and search.

Build a metrics pipeline that ingests high-volume events, aggregates time-series data, and powers operational dashboards and alerts.

Design a payment and ledger system that authorizes payments, records immutable financial movements, reconciles providers, and supports audited operations.

Design a ride-sharing dispatch system that matches riders with nearby drivers, tracks trips in real time, and handles pricing, acceptance, and cancellation events.

Design a collaborative editor where multiple users edit documents together with realtime updates, offline sync, version history, and conflict handling.

Build a telemetry ingestion platform for millions of devices, stream validation, time-series queries, alerting, and warehouse analytics.

Build a CI/CD orchestration service that schedules builds, runs isolated jobs, stores artifacts, streams logs, and supports retries and approvals.

Design a global video-streaming platform with upload and transcoding, adaptive playback, edge distribution, entitlement checks, personalized discovery, and resilient quality-of-experience telemetry.

Design a multi-tenant scheduler for one-time and recurring jobs with durable timing, fair dispatch, leases, retries, dependency workflows, and strong operational controls.

Design a large-scale recommendation platform with event ingestion, feature computation, candidate retrieval, model serving, ranking, experimentation, and safe fallback behavior.