Check your website's speed on mobile and desktop

A website speed check measures how long a page takes to show its content, become usable, and stop moving around, on both a phone and a computer. When Kite runs Google's PageSpeed Insights test, it gets the following for each device:

• Four scores out of 100. Performance is the speed score most people mean. The test also scores search basics, accessibility, and general best practices, so one check tells you about more than speed.
• The load timings behind the performance score. These include how long the first text or image takes to appear, how long the largest element takes to appear, how long the page is too busy to respond to a tap, and how much the layout jumps while it loads.
• Google's verdict from real visitors. When enough Chrome users have visited your site, Google reports how its loading experience rated for them over the previous 28 days.

The test takes up to about a minute per run. Kite can run it on your site or on a competitor's, which helps when you want to know whether a rival's site is noticeably faster than yours on phones.

Core Web Vitals are three measurements Google uses to describe how a page feels to a real visitor. The first is how quickly the main content appears, called Largest Contentful Paint. Google considers 2.5 seconds or less good. The second is how quickly the page responds when someone taps or clicks, called Interaction to Next Paint, where 200 milliseconds or less is good. The third is how much the layout shifts while the page loads, called Cumulative Layout Shift, where a score of 0.1 or less is good. Google's page experience signals combine these with whether your site uses a secure connection and works well on a phone.

The part most people miss is that Google judges Core Web Vitals on real visitors, not on the lab test. The lab test loads your page once on a simulated device. It can't measure how quickly a page responds to a real tap, so it reports blocking time as a stand-in. The real-visitor data comes from Chrome users who visited your site, and it is what Google's ranking systems use.

Kite reads both and tells you which is which. If your site has real-visitor data, Kite leads with it, because it describes what your customers actually experienced. If your site is newer or quieter and Google has no real-visitor data for it, Kite says so and relies on the lab test instead. That keeps you from either panicking about a lab score your visitors never felt or ignoring a real problem because the lab test happened to run well.

Your website is almost always slower on phones because phones have less processing power and slower connections, and many sites are built and checked on a fast laptop. Google's mobile test makes this visible on purpose. It imitates a mid-range phone on a slow mobile connection, which is why the same page can score 85 on desktop and 45 on mobile.

The causes tend to be the same handful of things:

• A large image or video at the top of the page that the phone has to download in full before the page looks finished.
• Scripts for chat widgets, analytics, ads, or animations that the phone has to run before it can respond to a tap.
• Fonts, banners, or embeds that load late and push the page's content down while someone is trying to read it.
• A page that simply downloads too much, often several megabytes of images that were never resized for a small screen.

Kite connects the slow timing to the likely cause. For example, if your homepage's main content takes 4.1 seconds to appear on a phone but only 1.6 seconds on a computer, and your hero image is a large photo served at full size, the image is the first thing to fix. If the page appears quickly but stays unresponsive, the scripts it loads are the place to look. On a site Kite hosts or a code repository you've imported, Kite reads the page's code to confirm the cause before it proposes a change.

Kite tests the pages that lead to revenue, because a slow pricing or signup page costs you more than a slow blog post. Most speed tools test whatever single address you give them, and most people only ever test their homepage.

When your team signs up, Kite times your homepage on phones along with up to three key pages it finds on your site. It picks your pricing page, your signup page, and your documentation, and it uses your demo, booking, or contact page in place of a missing signup page. For each one, it uses real-visitor timing when Google has it and runs the lab test when it doesn't, and it labels which is which. It then names the slowest of those pages. The results go into the growth report Kite delivers on your company, alongside its other research on your website.

Kite also has your own traffic in view. On a site it hosts, its built-in analytics show which pages people visit most and how your visitors split between phones and computers. If most of your visitors arrive on phones, Kite treats the mobile results as the ones that matter most.

Kite fixes speed problems directly on a website it hosts. It can resize and compress heavy images, change layouts so they work better on small screens, and fix errors that stop a page from displaying properly. New sites Kite builds already serve smaller images to phones, so most speed work on a Kite site is about pages and media added since launch.

Every change waits as an unpublished change you can preview before it goes live. When you publish, Kite shows the list of changes, ships them together, and checks that the site displays correctly. You can undo any single change if you don't like the result.

If your site lives in a GitHub repository you've imported, Kite makes the change in the code and merges it into your main branch, or opens a pull request if you protect that branch. Your own deployment then ships it. If your site runs on a website builder or content system that Kite doesn't host, Kite tells you which pages are slow and what is causing it, so your team or your developer knows exactly where to start.

Kite checks your site's speed again shortly after every publish on a site it hosts. About a minute and a half after a publish goes live, it runs Google's mobile test on your homepage along with a few search checks. It emails the person who published if the mobile performance score falls below 50, if the search basics score falls below 90, or if the homepage downloads more than 5 megabytes.

The check warns and never blocks, so a publish always goes through. Each problem is reported once, and Kite reports it again only if it comes back after being fixed. If Google's test can't run, for example because Google's service is busy, Kite skips that check rather than telling you your site is broken.

You can also ask Kite to run a full speed check on a schedule, such as the first Monday of every month, so you can see whether a fix worked and catch a slowdown before your visitors complain.