The full list

Every check we run, and why

122 checks across 7 areas. Each one has its own page explaining what it looks for, why it costs you something, and how to fix it — whether or not you ever run a scan.

Run them all on your site

Search

55 checks

Speed

19 checks

Every page gets the files it asks forA file that is missing on one template is missing on every page built from it, which is usually hundreds of pages rather than one. It is also the hardest kind to notice from the inside: a browser that has an older copy of the file will carry on showing it long after the file itself has gone, so the site looks correct to whoever built it and broken to everybody arriving fresh.performance.failed-requests-sitewide
Every page responds promptlyWhen one part of a site responds noticeably slower than the rest, it usually points at one specific thing rather than at the hosting in general — a heavy search query, an unindexed database lookup, or a page rebuilding something on every request. That makes it one of the more fixable speed problems, because there is a single cause to find.performance.slow-pages
Everything the page asks for loadsYour page requests these and gets nothing back. Depending on what they are, that means a missing image, a stylesheet that never applies, or a script that never runs — and the page may look fine to you if your browser has an older copy cached.performance.failed-requests
First visit after a quiet spell is not slowSome hosting puts a site to sleep when nothing has visited for a while, and the next request has to wake it. Once warm the site is fine, which is why this is easy to miss — the person testing it has usually just loaded the page. The people who get the slow version are the ones arriving overnight, and Google when it crawls at an odd hour.performance.slow-cold-start
Google has enough visitor data to report on your siteGoogle publishes real-visitor speed figures for a site only once enough Chrome users have been there to make the numbers meaningful and anonymous. Below that threshold there is nothing to publish, which is the ordinary situation for a small business site and says nothing about how well the site is built. It does mean every speed figure in a report like this one is a simulation rather than a record of what happened to anybody.performance.no-field-data
Images reserve their space before loadingThe browser cannot tell how tall these images will be until they have downloaded, so it draws the page without them and then pushes everything down when they arrive. That is the jump people experience as a page moving under their thumb.performance.images-missing-dimensions
Main content appears quickly on a phoneThe largest thing on the page — usually the main image or headline — is what a visitor is waiting for. Until it finishes loading they are looking at a blank or half-built page. This is measured on a mid-range phone on mobile data rather than on a fast desktop connection, because that is the harder case and the one most visitors are actually in.performance.slow-lcp
Main image is sized for the screenWhen the biggest image on the page is far wider than the space it is shown in, visitors download image data they can never see — and image data grows with the square of the width, so an image at twice the needed width is roughly four times the bytes. It is paid for on the connection least able to afford it.performance.oversized-lcp-image
No errors on the rest of your pages eitherScripts fail by template rather than by site. A gallery that throws only where there is a gallery, a booking widget that throws only on the booking page — checking the home page finds none of it, and neither does the owner, whose browser has a working version cached from before whatever broke it. It is one of the few faults where the people affected are exactly the people who never mention it, because they assume the site is meant to be like that.performance.console-errors-sitewide
No errors while the page loadsSomething on the page is failing every time it loads. Often it is a harmless third-party script, but it is also how a broken booking form, a dead tracking tag or a checkout that silently fails shows up — none of which announce themselves to the person running the site.performance.console-errors
Nothing from another company holds up your first paintA stylesheet or script in the head of a page stops the browser drawing anything until it has finished downloading. When that file is on another company's server, the visitor is looking at a blank screen while a machine you do not control decides how fast to answer — and it needs a fresh connection to be opened before it can even start. A font service or a tag manager loaded this way is the most common cause, and both have a supported way of loading that does not block.performance.third-party-blocking
Nothing needless blocks first paintThe browser will not draw a single pixel until certain stylesheets and scripts have finished downloading. On a phone that is dead time the visitor spends looking at nothing. It is worse when one of those files is pulled in by an @import inside another stylesheet, because it cannot even start downloading until the first has arrived.performance.render-blocking-resources
Other companies' code is a small share of your pageAnalytics, chat widgets, advert tags, embedded video players and social buttons all download code from somebody else's servers before your page is finished. Each one arrived for a reason, but they accumulate — nobody ever removes a tag — and they are downloaded over the visitor's connection, not yours. This is one of the few speed problems where the fix is a decision rather than a development project: something on the list is usually a tool the site stopped using and nobody switched off.performance.third-party-weight
Our measurements match what your visitors actually getA scan loads a site once, on one connection, from one place. Google's figures come from four weeks of real Chrome visitors on whatever devices and connections they happened to have. When the two disagree it is worth knowing which way: a site that tests well and performs badly for real people usually has slow pages beyond the one that was tested, or visitors on worse phones than the test assumes. A site that tests badly and performs well in the field is being judged too harshly by the test, and saying so is more useful than defending the number.performance.lab-and-field-disagree
Page is light enough for mobile dataSomeone on mobile data pays for every megabyte a page downloads, and waits for them. A heavy page is usually a handful of images that were never resized rather than anything structural, which makes it one of the cheaper speed problems to fix.performance.heavy-page
Page stays responsive while loadingA phone can only do one thing at a time. While scripts are running, taps and scrolls are queued rather than acted on — which reads to a visitor as the site being frozen, not as it being slow. They tend to tap again, and then leave.performance.blocking-scripts
Page stays still while loadingContent moves after it first appears, so someone reading or reaching for a button can have it shift under them. This is what causes the mis-taps that make a site feel broken on a phone.performance.layout-shift
Server responds promptlyThis is how long your hosting takes to begin sending the page at all — before any images, fonts or scripts have started. Every other speed improvement is stacked on top of this delay, so when it is slow it is the one to fix first.performance.slow-ttfb
Your site reacts quickly when real visitors tap itResponsiveness is how long a page takes to visibly react after somebody taps it — not how fast it loads, but whether it feels stuck once it has. It is the one thing a scan genuinely cannot measure, because there is nobody there to do the tapping, so a synthetic test can only estimate it from how busy the page looks. Where Google has collected the figure from real Chrome visitors, it is a measurement rather than an estimate, and it is usually caused by scripts doing work in response to the tap itself.performance.field-inp-poor

Security

16 checks

Trust

15 checks

Privacy

5 checks

AI readiness

2 checks