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Caching and Performance Optimization Questions

Covers design and implementation of multi layer caching and end to end performance strategies for web and backend systems. Topics include client side techniques such as browser caching, service worker strategies, code splitting, and lazy loading for components images and data; edge and distribution techniques such as content delivery network design and caching of static assets; and server side and data layer caching using in memory stores such as Redis and Memcached, query result caching, and database caching patterns. Includes cache invalidation and coherence strategies such as time to live, least recently used eviction, cache aside, write through and write behind, and prevention of cache stampedes. Covers when to introduce caching and when not to, performance and consistency trade offs, connection pooling, monitoring and metrics, establishing performance budgets, and operational considerations such as cache warm up and invalidation during deploys. Also addresses higher level concerns including search engine optimization implications and server side rendering trade offs, and how performance decisions map to user experience and business metrics at senior levels.

HardTechnical
27 practiced
Describe and design an implementation of stale-while-revalidate (SWReval) across CDN and origin caches. Explain how you would implement it end-to-end, how you prevent a stampede of revalidations, and how you ensure origin doesn't get overloaded during large-scale revalidation events.
HardTechnical
35 practiced
Compare and analyze the trade-offs of performing personalization at the edge using edge functions (e.g., Cloudflare Workers, Lambda@Edge) vs performing personalization server-side and delivering fully personalized HTML. Consider latency, cacheability, operational complexity, and data privacy.
MediumSystem Design
27 practiced
Design a client-side caching strategy for a single-page application used by authenticated users where large UI bundles and frequently-changing per-user data exist. Describe how you would use code splitting, lazy loading, service worker caching, and API caching together to optimize first-contentful-paint (FCP) and time-to-interactive (TTI) while maintaining data correctness.
HardTechnical
34 practiced
You need to design caching for an interactive analytics dashboard that requires data freshness within 5 minutes for aggregates computed over terabytes of raw events. Propose a hybrid approach using materialized views, incremental pre-aggregation, Redis/memory cache for hot dashboards, and batch/stream pipelines. Include freshness guarantees and how to surface staleness to users.
HardSystem Design
38 practiced
A user's shopping cart must remain consistent across devices and support offline edits. Architect a cache and persistence strategy to ensure correctness while keeping latency low. Discuss choice of data store, conflict resolution, sync mechanisms, and cache invalidation when a cart is modified on another device.

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