I started with content delivery and worked backwards, which in hindsight was a weird entry point.
Start by clarifying requirements and scale (e.g., number of users, content size, global reach) to set the scope. Then outline a high-level architecture covering content ingestion, storage, delivery, and user-facing services, and dive into key components like CDN, transcoding, and recommendation. Finally, discuss trade-offs and bottlenecks, and how you would monitor and scale the system.
Pro tip: Emphasize the importance of adaptive bitrate streaming and CDN caching for user experience, and proactively discuss how you'd handle failures and ensure high availability across regions.
Ask questions to understand functional and non-functional requirements: number of users, concurrent streams, content library size, global availability, device types, and key features like recommendations and offline downloads.
Sketch the main components: client apps, API gateway, user service, content ingestion and encoding pipeline, storage (object store), CDN, recommendation engine, and analytics. Explain data flow from content upload to playback.
Pick 2-3 components to detail, such as video transcoding (formats, bitrates), CDN strategy (edge caching, geo-distribution), and recommendation system (collaborative filtering, real-time updates). Discuss technologies and design choices.
Explain how the system scales horizontally, handles failures (redundancy, failover), and ensures low latency. Discuss trade-offs like consistency vs. availability, cost vs. performance, and build vs. buy.
Mention monitoring (metrics, logging, alerting), A/B testing, and potential enhancements like personalization, live streaming, or new markets. Summarize key decisions and invite feedback.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.