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Topicimplementation (105)system-design (24)hld (20)trees (11)distributed-systems (10)arrays-hashing (9)concurrency (9)graphs (9)binary-search (8)consistency (8)dp-1d (8)linked-list (8)reliability (8)storage (8)
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- Design a notification serviceDelivery guarantees when every downstream provider is someone else and fails.mediumWrittenExplain to unlock#hld#queues#reliability45 min
- Design a rate limiterSmall surface, deep follow-ups. The distributed counter race is the real question.mediumWrittenExplain to unlock#concurrency#hld#reliability45 min
- Design a retry policyRetries are the most common way a small outage becomes a large one.mediumWritten#distributed-systems#lld#reliability25 min
- What does idempotent actually mean?Everyone can list which verbs are idempotent. Far fewer can make a payment endpoint safe to retry.mediumWrittenExplain to unlock#api-design#reliability#rest20 min
- Design a distributed job schedulerLeader election and at-least-once done properly, with dependencies.hardWrittenExplain to unlock#distributed-systems#hld#reliability45 min
- Design a metrics and monitoring systemWrite-heavy, and cardinality is what actually kills these systems.hardWrittenExplain to unlock#hld#reliability#storage45 min
- Design a payment system and ledgerCorrectness over throughput. Money makes every shortcut visible.hardWrittenExplain to unlock#consistency#hld#reliability45 min
- Design an object storage serviceDurability arithmetic, and the metadata service that is the real bottleneck.hardWrittenExplain to unlock#hld#reliability#storage45 min