Chapter 60: Core Web Vitals & Performance Engineering

Real User Monitoring (RUM) with web-vitals

**Part 12: Performance & Optimization** — Chapter 60: Core Web Vitals for HTML Developers

LEARNING OBJECTIVES ⌵
  • Integrate Google's standard web-vitals JavaScript library (1.5KB).
  • Capture LCP, INP, CLS, FCP, and TTFB metrics from real production users.
  • Stream performance analytics beacons using navigator.sendBeacon().
  • Segment performance metrics by device type, country, and network tier.
🎬 INTERACTIVE VISUAL PIPELINE Core Architecture Simulation
🌐
1. Input
Directives & Tags
⚙️
2. Parse
Tokenizer & AST
🌳
3. Layout
Box Model & Flow
🎨
4. Render
GPU Paint & Composite
PHASE 1: INPUT & DIRECTIVES
Browser receives declarative markup stream, parsing tag tokens and initializing component state.

💻 Interactive Code Playground

SYS: ACTIVE
HULL: 98%
CORE: STABLE
NET: ONLINE
HTML STARSHIP CODE TERMINAL playground.html
root@STARSHIP-ALPHA:~/web-core# READY FOR COMPILATION █
LIVE RENDER & DIAGNOSTICS CORE TEMP: 45°C
INSPECTING DOM: VALID
TAGS: SCANNING...

📌 Key Takeaways

  • Real User Monitoring (RUM) captures metrics from diverse real-world mobile devices and network conditions.
  • navigator.sendBeacon() guarantees that performance metric telemetry is transmitted reliably even during page unloads.
  • --

❓ Knowledge Check

1. Which of the following is correct?

2. Which of the following is correct?