The Critical Rendering Path is the sequence of steps browsers take to render a page: HTML parsing, CSS parsing, render tree construction, layout, and paint. Optimize by minimizing critical resources, reducing file sizes, and removing render-blocking resources.
Critical Rendering Path Steps:
Blocking Resources:
Optimization Strategies:
<!DOCTYPE html>
<html>
<head>
<!-- Preconnect to critical origins -->
<link rel="preconnect" href="https://fonts.googleapis.com">
<link rel="preconnect" href="https://api.example.com">
<!-- Preload critical resources -->
<link rel="preload" href="/fonts/main.woff2" as="font" type="font/woff2" crossorigin>
<link rel="preload" href="/hero.jpg" as="image">
<!-- Critical CSS inlined -->
<style>
/* Above-the-fold styles only */
body { margin: 0; font-family: system-ui; }
.hero { height: 100vh; background: #f0f0f0; }
.nav { position: fixed; top: 0; width: 100%; }
</style>
<!-- Non-critical CSS loaded asynchronously -->
<link rel="preload" href="/styles.css" as="style" onload="this.onload=null;this.rel='stylesheet'">
<noscript><link rel="stylesheet" href="/styles.css"></noscript>
<!-- Scripts with appropriate loading strategy -->
<script src="/critical.js"></script> <!-- Blocking if needed -->
<script src="/analytics.js" async></script> <!-- Independent -->
<script src="/app.js" defer></script> <!-- After DOM -->
</head>
<body>
<!-- Content... -->
</body>
</html>