System Design Card 434 — CDN and Media Delivery / Implement
Concern
Static and media-heavy workloads often need edge distribution rather than central-origin delivery for acceptable performance. Image-serving, file download, and streaming content systems depend heavily on caching at the edge.
What Implement means for this concern
In BASIC, the Implement step is where you walk the design into existence in a controlled order, deepening the risky parts first. For CDN and Media Delivery, that means the candidate should make this concern visible at the right moment instead of bolting it on at the end.
Design move
A good move is to transcribe the plan instead of improvising. Tie the concern back to the user flow, the workload, and the dominant trade-off. That keeps the design grounded and makes it easier for the interviewer to follow why a cache, queue, replica, partition, or rate limiter is actually necessary.
Common miss
The miss is treating global content delivery like ordinary API traffic. BASIC helps because the staged flow keeps this concern proportional to the prompt and connected to the rest of the architecture.
BASIC prompt
“When I reach the Implement stage, how does CDN and Media Delivery change the architecture, the trade-offs, or the review checklist?”