Design a Leaderboard
Listed inDesign a LeaderboardSystem Design Questionson
Ranked sets at scale, real-time score updates, and answering "what is my rank" without scanning.
Intermediate8 minDraft
#interview
The classic problems, worked end to end — requirements, estimates, data model, high-level design, then the deep dive an interviewer actually pushes on.
20 articles
Listed inDesign a LeaderboardSystem Design Questionson
Ranked sets at scale, real-time score updates, and answering "what is my rank" without scanning.
Listed inDesign a Key-Value StoreSystem Design Questionson
Partitioning, replication, quorum reads and writes, and conflict resolution when two writers disagree.
Listed inDesign a Chat SystemSystem Design Questionson
Long-lived connections, presence, message ordering, delivery receipts, and offline sync.
Listed inDesign a Ticket Booking SystemSystem Design Questionson
Inventory that must never oversell: holds, expiry, and the transaction boundary under a flash sale.
Listed inDesign a Distributed CacheSystem Design Questionson
Consistent hashing, eviction policy, replication, and what happens to the database when a node dies.
Listed inDesign a Rate LimiterSystem Design Questionson
Token bucket versus sliding window, where the counter lives, and staying correct across many instances.
Listed inDesign a News FeedSystem Design Questionson
Fan-out on write versus read, ranking, pagination that stays stable, and the celebrity account problem.
Listed inDesign a Ride-Hailing ServiceSystem Design Questionson
Location ingest at high write volume, proximity search, matching, and state machines for a trip.
Listed inDesign a Metrics and Monitoring SystemSystem Design Questionson
Time-series ingest, downsampling, retention tiers, and alert evaluation without re-reading everything.
Listed inDesign a URL ShortenerSystem Design Questionson
The canonical warm-up: key generation, collision handling, redirect latency, and read-heavy caching.
Listed inDesign a Notification SystemSystem Design Questionson
Fan-out across push, SMS, and email, with retries, deduplication, and per-user preferences.
Listed inDesign a File Storage ServiceSystem Design Questionson
Chunking, deduplication, delta sync, and resolving conflicts when two devices edit while offline.
Listed inDesign a Distributed Job SchedulerSystem Design Questionson
Cron at scale: leader election, at-least-once execution, backoff, and jobs that must not run twice.
Listed inHow to Approach the InterviewSystem Design Questionson
A repeatable 45-minute structure: clarify, estimate, sketch, deep-dive, then name the bottlenecks yourself.
Listed inDesign a Web CrawlerSystem Design Questionson
Frontier queues, politeness, deduplication, and trap detection at a scale where restarts are normal.
Listed inDesign a Video PlatformSystem Design Questionson
Upload, transcoding pipelines, adaptive bitrate streaming, and CDN economics at YouTube scale.
Listed inDesign an Ad Click AggregatorSystem Design Questionson
High-volume event ingest, windowed aggregation, late-arriving data, and exactly-once counting.
Listed inDesign a Unique ID GeneratorSystem Design Questionson
Snowflake-style IDs, clock skew, and why auto-increment stops working the moment you shard.
Listed inDesign Search AutocompleteSystem Design Questionson
Prefix tries, top-k per prefix, and updating the index without blocking a sub-100ms read path.
Listed inDesign a Payment SystemSystem Design Questionson
Idempotency, the ledger, reconciliation with a provider, and why money never uses a float.