Page load is fast enough on mobile

Many users of your page visit over a slow cellular network connection. Ensuring that your page loads fast over a simulated mobile network ensures that your page loads in a reasonable amount of time for your mobile users. Lighthouse flags any pages that don't load fast enough on mobile:

Lighthouse audit showing page doesn't load fast enough on mobile
Fig. 1 — Page doesn't load fast enough on mobile

A fast page load on a mobile network is a baseline requirement for a site to be considered a Progressive Web App. See Baseline Progressive Web App Checklist.

How this audit fails

There are two main metrics regarding how users perceive load time:

  • The page appears visually complete.
  • The page is interactive. If a page appears visually complete at 1s, but the user can't interact with it until 10s, then the perceived page load time is 10s.

Lighthouse computes what time to interactive would be on a slow 4G network connection. If the time to interactive is more than 10s, the audit fails.

Each PWA audit is weighted equally in the Lighthouse PWA Score, with the exception of three manual audits: Site works cross-browser, Page transitions don't feel like they block on the network, Each page has a URL. Learn more in The Progressive Web App score.

Recommendations

To speed up time-to-visually-complete, only load the resources you need in order to display the page. See Critical Rendering Path and Optimizing Content Efficiency.

To speed up time-to-interactive, only execute the JavaScript that you need in order to display the page, and defer the rest. See Get Started With Analyzing Runtime Performance to learn how to analyze JavaScript execution with Chrome DevTools.

Record load performance shows you how to record a page load. Once you're familiar with the basics, do a page load recording and analyze the results to find JS work that can be deferred. See Rendering Performance for strategies.

More information

Page doesn't load fast enough on mobile audit source

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