PageSpeed: Network Dependency Tree

Pages with a lot of latency on the critical path, caused by long chains and large resource download sizes.

Additionally, pages with key requests that aren’t yet prioritising fetch requests with link rel=preconnect to establish early connections to important third-party origins.

This audit is a consolidation of two previously separate audits in Lighthouse – Avoid chaining critical requests and Preconnect to Required Origins.

How to Analyse in the SEO Spider

To populate this filter the PageSpeed Insights API must be connected via ‘Config > API Access > PSI’.

View URLs with this issue in the ‘PageSpeed’ tab and filter and use the lower ‘Lighthouse Details’ tab to click on the issue on the left-hand side, and see details of the critical path latency and preconnect candidates on the right-hand side.

Bulk export the pages and images via ‘Reports > PageSpeed > Network Dependency Tree’.

What Triggers This Issue

This insight only fails if a critical request is not discoverable early in the page.

A request is considered critical if it is potentially render-blocking or high priority.

How To Fix

Avoid chaining critical requests by reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load.

Consider adding preconnect or dns-prefetch resource hints to establish early connections to important third-party origins.

In general, try to use link rel=”preload”, as it’s a more comprehensive performance tweak.