Google’s John Mueller answered if Chrome-based spam traffic could negatively impact Web Vitals scores. John Mueller isn’t on the Chrome team or the web platform, so he had to pause to think about it for a second before responding.
One of the implications, an underlying question, is whether it is possible to launch a negative SEO attack focused on poisoning Core Web Vitals and thereby affecting a known ranking factor.
Chrome User Experience Report
The Core Web Vitals scores that become ranking factors are derived from real users on Chrome browsers.
Browsing information contains real web page download data from real devices visiting real web pages.
This data is what Google calls “field data” and is what is used to calculate the Core Web Vitals score which is then used as a ranking factor.
Google uses browsing data from Chrome Browser users to create the Chrome User Experience Report.
Google’s developer pages describe the process as follows:
“The Chrome User Experience Report is powered by actual user metrics of top user experience metrics across the public web, aggregated from users who opted in to sync their browsing history, didn’t configured sync passphrase and have enabled usage statistics reporting.”
True Chrome users can impact Core Web Vitals scores.
So the person asking the question had a legitimate concern.
The person who asked the question called it “spam traffic” that “uses Chrome as a browser”.
The person doesn’t know if they were real people using Chrome browsers on slow connections or if they were bots.
John Mueller unfortunately did not ask for clarification.
Bots spoof Chrome
There are many kinds of bots that aren’t Chrome, they just mimic Chrome (this is called Chrome User Agent Spoofing).
For example, a Python-based web scraper can spoof Chrome to trick a website into thinking it’s just a normal site visitor.
These types of bots will not affect a website’s Web Vitals scores because they are not Chrome, they are just scripts.
Headless chrome robots
There are other types of bots based on the real Chrome browser, called Headless Chrome.
Headless Chrome is the Chrome browser but without Chrome UI, that’s why it’s called headless.
It is unlikely that the Headless Chrome browser can also return Core Web Vitals information, as Headless Chrome is designed for testing purposes.
Spam traffic with real people using Chrome
The nightmare scenario is that spammers send real people on a slow internet connection to visit a site while using Chrome browsers that are enabled for Page Experience Reporting.
How would Google filter out real people using Chrome with bad intentions to not negatively impact Core Web Vitals?
Related: How to Filter Referral Spam in Google Analytics
Can Chrome-Based Spam Traffic Influence Core Web Vitals?
The person asking the question called it “spam traffic” and didn’t specify whether it was human spammers or bots.
This is the question asked:
“Over the past week, we’ve seen a huge increase in direct spam traffic to some of our websites, coming from all over the world using Chrome as their browser.
This spam traffic is very slow. We’re a little concerned about the Chrome metrics that are used to gauge page speed and ranking.
Does Google know? Is there anything we can do? »
Google Responds if Chrome Spam Traffic Affects Core Web Vitals
Jean Mueller replied:
“Um…So…I don’t know…we see a lot of weird spam traffic on the web over time and we have a pretty good understanding of that.
And the way that, as I understand it, in terms of the major vitals of the web, what we’re using…in the Chrome user experience report data, there are certain requirements that we monitor and we filter almost certainly the usual spam traffic is also there too.
From that perspective, I wouldn’t expect it to cause any problems.
If you’re really worried about this and can send me some data, I’ll be happy to pass it on to the Chrome team so they can take a look.
But I wouldn’t assume that would cause any problems.
We see all kinds of weird spam traffic all the time and our systems are pretty tuned to avoid that sort of thing.
Can Google catch Chrome-based spammers?
It seems pretty clear that a Headless Chrome bot would not affect base Web Vitals scores. I couldn’t find any documentation that says this explicitly, but it seems like it should be. It would be nice to have some clarification from Google.
John Mueller is convinced that the Chrome User Experience Report filters out “usual spam traffic”.
But he also offered to pass the information to the Chrome team for review.
How to do you feel it?
Does Chrome-Based Spam Traffic Impact Core Web Vitals?
Watch John Mueller answer the question after 30 minutes: