The Full Page Check monitor (FPC monitor) provides performance data down to page element level. The FPC monitor has been around for some years and it was about time for an overhaul. We’ve improved some of the existing functionality and added a number of cool features.
Changed features
A number of existing features have changed, which could mean different use or (slightly) different results. Please check the list below for detail on what to expect.
Content match
The content matching works differently now. Previously, FPC content matching was done on all HTML content that was sent to the browser, including content on redirect pages. For the new FPC, only the final result is considered when matching content. Content shown during a redirect will no longer trigger a content match.
URL blocking
The URL blocking feature is different in the new FPC. When navigating to a site, the navigate will succeed, even if the URL of that site is listed in the blocked URLs list. This is because the new FPC no longer blocks navigation. Other elements that the site references such as images will be blocked as before.
New measuring techniques
The timings and total bytes are different from measurements that are taken by the former FPC.
The new FPC supports new protocols such as HTTP2 and HTTP3, and is more closely integrated with the browser. As a result, the waterfall generated can differ from that of an old FPC. You can expect to see more simultaneous requests, that transfer more quickly. Because the measurement can be quicker or slower, the total bytes could also differ from the old FPC, because we capture a different amount of background activity after the page load (e.g. a video that is loading, or a JavaScript serviceworker that is performing background tasks).
W3C total time or Total time?
With the new FPC we also provide the option to measure the total time as the W3C load event, instead of our usual way of measuring total time by waiting for an idle period of network activity. The W3C load event is described in further detail here: https://www.w3.org/TR/navigation-timing/#dom-performancetiming-loadend
To make your choice, go to the Advanced tab of the monitor settings. In the Measurement section select one of the options within the Base load time on :
Headers
Requests done by new protocols such as HTTP2, HTTP3 and QUIC will also have different headers. The new FPC will no longer use X-Uptrends headers, such as X-Uptrends-PortInfo and X-Blocked-By-Uptrends.
New features
In addition to changing and improving some of the existing functionality, we also introduce a number of new features.
Native checks
The new FPC measures performance directly within the browser, and no longer needs a proxy to collect information. This allows the browser to function as close to natural as possible.
Core Web Vitals
Core Web Vitals are standard metrics from Google that are used to understand the performance of your website. Uptrends now measures and reports those metrics in the check results.
Those measurements may be different than what is measured with the Lighthouse tool. The Lighthouse tool provided by Google uses a different measuring technique than Uptrends. We run a browser that visits a website just like a normal user would. The Lighthouse tool first runs a warmup and then visits the site several times to determine an average. The Lighthouse tool also does not trigger certain user input checks, that our measuring technique and normal users do. It also simulates a slower connection with throttling. This is why the Core Web Vitals reported by Lighthouse can differ from Uptrends measurements.
Please visit the article on Core Web Vitals to learn all about the new metrics.
W3C metrics
The Word Wide Web Consortium (W3C) has defined a set of navigation timings that are essential to loading a web page. Uptrends has adopted several of those timings to measure and show in reports.
Check out the KB article W3C navigation timings to find out the details about the implemented navigation timings.
Timeline screenshots
The timeline of screenshots (aka filmstrip) is a totally new feature. It contains a number of screenshots that are taken while the monitored webpage is loading. The timeline is presented above the waterfall in the monitor check details:
HTTP2, HTTP3, QUIC
In addition to the HTTP protocol, the FPC monitor now also supports the HTTP2, HTTP3 and QUIC protocol.
Cached elements
Because we extract performance information from the browser, we can now also show cached elements that we couldn’t detect with our proxy-based measuring technology. It is possible to filter them if so desired.
Data URLs in waterfall
Elements that are embedded inside the HTML document, such as data URLs, or that come from JavaScript, such as Blob URLs, are also shown in the waterfall. You can apply a filter if needed.
TLS information
In the waterfall of the monitor check details you can now find TLS information for each element. You can open the details from the waterfall by clicking on the plus sign next to the element:
How to switch on the new features
If you want to use the new features for your FPC monitor(s), you have to actively switch this on for individual monitors. Keep in mind that this works only for Google Chrome browsers.
To switch on the new features:
- Open an existing monitor or create a new one.
- Go to the Main tab.
- In the Details section choose the Browser type “Chrome with extra metrics”.
- Click .