System Design - scalability
#01 Scalability

Build Google Search Autocomplete Premium

Design a typeahead suggestion engine that returns the top 10 relevant completions for any search prefix in under 50ms, personalizes results per user, and updates suggestions based on trending queries in near real-time.

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#02 Scalability

Build Instagram Explore Real-Time Recommendation Engine Premium

Design a content discovery system that generates a personalized Explore grid for 2 billion users, refreshes recommendations as users scroll, and surfaces trending content within minutes of it going viral.

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#03 Data Engineering

Build Instagram Stories Expiry and Archival Pipeline Free

Design a system that automatically expires 500 million Stories after 24 hours, moves them to cold archival storage, and lets users retrieve archived Stories on demand without impacting live traffic.

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#04 Databases

Build an Inverted Index for Full-Text Search at 10B Documents Premium

Design a full-text search engine that builds and maintains an inverted index over 10 billion documents, returns results with relevance ranking in under 100ms, and updates the index in near real-time as documents are added.

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#05 Scalability

Build Meta's Notification Delivery System Premium

Design a notification platform that routes alerts across push, in-app, SMS, and email channels, handles traffic spikes of 10x during viral events, and respects per-user notification preferences in real-time.

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#06 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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#07 Scalability

Build Netflix Adaptive Bitrate Streaming Engine Free

Design the client-side ABR algorithm and server-side infrastructure that switches video quality in real-time based on available bandwidth, minimizing rebuffering while maximizing perceived quality.

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#08 Data Engineering

Build Netflix's Recommendation Engine Premium

Design a personalization engine that generates a unique homepage for 280 million users, blends collaborative filtering with content-based signals, and updates recommendations within hours of new viewing behavior.

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#09 Performance

Build a Personalized Typeahead Search Engine Premium

Design a search suggestion system where the same prefix returns different top results per user based on their history, while still surfacing globally trending queries and completing within 50ms end-to-end.

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#10 Data Engineering

Build a Podcast Transcription and Chapter Detection Pipeline Premium

Design a pipeline that transcribes uploaded audio in near real-time, identifies natural topic boundaries to auto-generate chapter markers, and makes the full transcript searchable within minutes of upload.

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