Opening Scenario
You launch a web app. Users in San Francisco load it in 200ms. Users in Frankfurt wait 2.5 seconds. Your server is in us-east-1. The JavaScript bundle is 800KB. Every user in Europe is fetching that bundle across the Atlantic, every time. You need your assets closer to your users — without running servers in every region yourself.
Question Progression
1. Why does geography affect load time if the internet is fast?
Question: Fiber-optic cables carry data at roughly two-thirds the speed of light. A round trip from New York to Frankfurt and back is about 70–80ms just in signal propagation over fiber, and 80–100ms in practice with routing overhead. Your app makes 20 requests to load. What does that add up to, and why does it matter?
Reasoning: A single HTTP/1.1 request-response cycle requires at least one round trip. A new connection also…
In the full tutorial
- Closing: When to Reach for This