Performance / Quiz
Where Did the Latency Go?
TTFB vs render, Server-Timing, RUM vs lab, and attributing a slow page to the tier that actually owns it.
- Difficulty
- Easy
- Format
- Quiz
- Points
- 100
- Estimate
- 8 min
// MISSION BRIEF
Your Mission
"The page is slow" is a symptom, not a diagnosis. This quiz is about splitting perceived latency across tiers: what TTFB tells you, what the frontend owns, how Server-Timing and RUM help you attribute the delay, and why backend caching cannot fix a frontend problem.
// FIRST CONTACT
Battle teaser
A page feels slow but backend p95 is 120ms. The next place to look:
- AThe frontend: render-blocking JS/CSS, hydration, large assets; backend speed is only part of perceived load time
- BAdd more backend servers
- CThe database indexes, always
- DNothing, 120ms means the page is fast
Answers, scoring, hints, and the full battle stay sealed.
// SKILL TAGS
performancefrontendttfbrum