Making smartphone sites load fast

Webmaster level: Intermediate

Users tell us they use smartphones to search online because it’s quick and convenient, but today’s average mobile page typically takes more than 7 seconds to load. Wouldn’t it be great if mobile pages loaded in under one second? Today we’re announcing new guidelines and an updated PageSpeed Insights tool to help webmasters optimize their mobile pages for best rendering performance.

Prioritizing above-the-fold content

Research shows that users’ flow is interrupted if pages take longer than one second to load. To deliver the best experience and keep the visitor engaged, our guidelines focus on rendering some content, known as the above-the-fold content, to users in one second (or less!) while the rest of the page continues to load and render in the background. The above-the-fold HTML, CSS, and JS is known as the critical rendering path.

We can achieve sub-second rendering of the above-the-fold content on mobile networks by applying the following best practices:

• Server must render the response (< 200 ms)
• Number of redirects should be minimized
• Number of roundtrips to first render should be minimized
• Avoid external blocking JavaScript and CSS in above-the-fold content
• Reserve time for browser layout and rendering (200 ms)
• Optimize JavaScript execution and rendering time

These are explained in more details in the mobile-specific help pages, and, when you’re ready, you can test your pages and the improvements you make using the PageSpeed Insights
tool.

As always, if you have any questions or feedback, please post in our discussion group.

Posted by Bryan McQuade, Software Engineer, and Pierre Far, Webmaster Trends Analyst