Google’s PageSpeed Insights adds two new metrics to the PageSpeed Insights API and Lighthouse’s UI. Two indicators marked as experimental are now being collected for field data, while corresponding laboratory data can be used for diagnostic purposes.
Google Lighthouse Update
Lighthouse is now updated with two new metrics.
The new Lighthouse metrics are:
- Interaction with Next Paint (INP)
- Time to First Byte (TTFB)
Time to First Byte (TTFB)
Many people already know Time to First Byte, it’s been around for years, and some may already be familiar with it.
The Time to First Byte (TTFB) metric measures how quickly a server responds to resource requests.
Therefore, the importance of this metric is that it helps isolate one factor (server responsiveness) that can negatively impact all other page load metrics that follow.
This makes TTFB a very important censorship metric for diagnostic purposes.
Anyone focused on improving Core Web Vitals should give TTFB a possible quick win.
The change to TTFB is that for the first time it is available as a metric in the PageSpeed Insights results section.
Chrome will also be collecting and reporting TTFB field data for the first time.
Interaction with Next Paint (INP)
Interaction to Next Paint (INP) is a brand new metric for how long it takes to interact with the entire page, what google phone this”Overall Interaction Latency. “
The INP metric expresses the time it takes to interact with the entire page, in contrast to First Input Delay, which only measures the time it takes for a page to respond to a site visitor’s first interaction.
Google uses the example of a shopping page to illustrate the difference between a good INP and a bad one.
The example of a shopping page shows a clickable image that produces a larger close-up version.
An example of a poor response is when the user clicks on an image and then something happens while waiting for a larger image to download to the browser. There is no feedback response to the click.
An example of a good response is when the user clicks the same image, which immediately responds with a page load graphic that indicates that the request for the image has been received and is now loading.
Screenshots of web elements that are responsive
Above is an example of how the new INP metric measures all responsive elements of a web page to represent interactions with Next Paint.
Google’s Web.dev explains the new “Interact with Next Paint (INP)” metric:
“INP is a metric designed to represent the overall interaction latency of a page by selecting one of the longest interactions that occurs when a user visits the page.
For pages with less than 50 total interactions, INP is the worst-latency interaction.
For pages with a lot of interaction, the INP is usually 98% of the interaction latency. “
New PageSpeed Insights layout
These two new metrics can now be viewed in the PageSpeed Insights tool.
But it may take some time for the field data to appear because the field data comes from actual Chrome browser users who have opted to allow page speed data to be sent to Google to visit the site and log their data.
Core network vital signs scores are listed continuously (in desktop view).
Lighthouse then displays the second row of metrics:
- first rich paint
- Input
- TTFB
Screenshot of the new Lighthouse Metrics display
Chrome Lighthouse Extension
Another way to view new metrics is to use Chrome Lighthouse Extension.
The way to use it is to browse to any page and the box in the upper right corner of the browser will turn red or green depending on whether the page passes the Core Web Vitals metric.
Clicking on the box itself activates the display of CWV and experimental metrics.
Screenshot of Chrome Lighthouse extension
New Indicators Available in 3rd Party Tools
Many page speed tools that use Lighthouse in their analysis also display INP and TTFB metrics.
For example, WebPageTest.org now displays new metrics.
WebPageTest Lighthouse result screenshot
Page Speed Insights Update
There are other updates to the PageSpeed Insights tool.
A notable change is the speed with which results are displayed, which is achieved by simultaneously loading field and laboratory data.
Another change is that PageSpeed Insights will first try to parse HTTP redirects before sending them to Lighthouse for analysis. Previously Lighthouse would handle HTTP redirects when performing analytics.
Plus two other additional changes:
“Core Web Vitals (CWV) metrics (LCP, FID, CLS) are displayed directly below the CWV assessment.
We tightened the design to reduce verbosity and vertical space. “
Lighthouse data is more useful
The addition of these two metrics, TTFB and INP, makes all page speed tools that use Lighthouse analytics more useful. TTFB provides feedback on server-related issues that may be the cause of poor speed performance elsewhere, while INP provides a broader overview of page performance than before.
Citation
Read Google’s official INP interpreter
Interaction with Next Paint (INP)
Read Google’s recently updated TTFB explainer
Read the PageSpeed Insights release notes
Release Notes for PageSpeed Insights API and PageSpeed Insights UI
