Network Dependency Tree

Why It Matters

• Every level in the dependency chain adds at least one network round-trip, which can be 50–200ms on mobile connections.
• Deeply nested dependencies delay First Contentful Paint and Largest Contentful Paint because the browser discovers them too late.
• Third-party scripts often load their own dependencies, adding hidden depth to your tree.
• Understanding your dependency tree is the foundation for effective resource prioritization and preloading strategies.

How to Fix It

1. Preload critical resources. Use <link rel="preload"> for fonts, key images, or scripts that the browser would otherwise discover late.
2. Inline critical CSS. Embedding above-the-fold styles in <style> tags eliminates one dependency hop.
3. Reduce chain depth. Move deeply nested imports closer to the HTML — if a JS file loads another JS file that loads a font, preload the font directly from HTML.
4. Use HTTP/2 push or Early Hints (103) to send critical resources before the browser even asks for them.
5. Audit third-party scripts. Each third-party tag may spawn its own chain of requests. Defer or lazy-load non-critical third-party code.

Common Mistakes

• Preloading everything — only preload resources that are on the critical rendering path. Over-preloading wastes bandwidth.
• Ignoring third-party chains — analytics, chat widgets, and ad scripts often create deep dependency trees you don't see in your own code.
• Using synchronous <script> tags that block HTML parsing and extend the chain.
• Relying on HTTP/1.1 where connection limits (6 per domain) force resources to queue — switch to HTTP/2.