1 min lesson
The edge stack: CDN, WAF, TLS, Anycast
Use "Most of that traffic is latency-sensitive and a lot of it is expensive to serve" to describe the practical rule.
Step 1 of 2
Before a request ever touches your EKS cluster, it crosses four or five edge layers. In a Cursor system-design round, the candidates who lose are the ones who jump straight to pods and ingress and skip everything that happens at the planet's surface.
Cursor serves 1M+ daily active users from a desktop app that talks to backends for indexing, retrieval and model inference. Most of that traffic is latency-sensitive and a lot of it is expensive to serve. The edge is where you decide what gets cached, what gets blocked and which region a user lands in - before any of it costs you compute.
Walk the path a request takes, in order. Naming the layers buys you credibility before you've designed anything.
Learn more
Full explanation
The Edge Stack, Top to Origin
Interactive diagram. Tab through its regions; each focused region shows its detail in the panel below.
Read top-down - the request enters at the client and only the survivors reach origin. Each layer sheds or protects so the one below it does less work.
Learn more
Optional practice
Practice: The edge stack: CDN, WAF, TLS, Anycast
QAn interviewer asks why a CDN won't save you much on Cursor's model-completion traffic. What's the crisp answer?