System Design - reliability
#01 Distributed Systems

Build Google Drive's File Sync Engine Premium

Design a file synchronization system that detects changes on any device, propagates them to all other devices within seconds, handles concurrent edits, and resolves conflicts without data loss.

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#02 Security

Build a HIPAA-Compliant Tamper-Evident Audit Log Premium

Design an audit logging system for healthcare data where every record access and modification is logged immutably, the log itself cannot be altered without detection, and auditors can query it efficiently.

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#03 Data Engineering

Build a Medical Record Deduplication System Premium

Design a patient identity matching system that detects and merges duplicate patient records across hospital systems using probabilistic matching, handles conflicting data fields in the merge, and provides a full audit trail of merges.

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#04 Deployment

Build a Model Versioning and A/B Testing System for ML Premium

Design a model deployment system that safely rolls out new ML models alongside existing ones using traffic splitting, measures business metrics per model variant, and automatically rolls back when a new model underperforms.

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#05 Distributed Systems

Build a Multi-Agent Orchestration System with Shared Memory Premium

Design an orchestration layer where a planner agent decomposes a task, spawns specialized sub-agents in parallel, and coordinates their outputs through a shared memory store - with full observability into every agent's actions.

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#06 Distributed Systems

Build a Multi-Region Config Management System Premium

Design a configuration management system that propagates changes to 20 global regions in under 500ms, prevents config divergence between regions, and supports instant rollback when a bad config causes elevated error rates.

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#07 Databases

Build a Multi-Tenant Database System Premium

Design a database architecture that isolates tenant data, prevents noisy-neighbor query interference, and allows individual tenants to be migrated, backed up, or throttled independently - all on shared infrastructure.

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#08 Distributed Systems

Build a Real-Time Multiplayer Game State Sync System Premium

Design a game state synchronization system that keeps all players in a match consistent with sub-100ms latency, handles lag compensation so fast-network players don't have an unfair advantage, and recovers gracefully when a player disconnects.

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#09 Distributed Systems

Build a Payment Processing System with Idempotency Guarantees Premium

Design a payment system that safely retries failed transactions without double-charging users, handles partial failures across payment provider integrations, and maintains a consistent ledger under concurrent requests.

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#10 Reliability

Build a Push Notification Routing System Premium

Design a notification dispatch system that routes messages across APNs, FCM, and Web Push, guarantees at-least-once delivery with deduplication, and handles delivery failures with smart retry strategies.

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