Other data

We collect information that can’t be used to identify users. Nevertheless, we’re giving website-owners the option to opt-in to some of them themselves, allowing full control over what is being measured and how close their tracking snippet will be to privacy regulations.

Tracked dimensions

A few examples:

  • conditions
    bandwidth (in Mbps) and its category (via navigator.connection.effectiveType)
  • device information:
    memory, pixel ratio
  • user preferences:
    dark mode, reduced motion

In the case of bandwith, bandwidth category and device memory, the precision of the information is already reduced by browsers to prevent fingerprinting. However, we have seen strong correlations with the information available and pagespeed metrics. This means that the information that browsers are providing are sufficient enough to put that data in buckets and spot correlations with metrics.

device memory

The reported value is imprecise to curtail fingerprinting. It's approximated by rounding down to the nearest power of 2, then dividing that number by 1024. It is then clamped within lower and upper bounds to protect the privacy of owners of very low- or high-memory devices

via developer.mozilla.org


The effectiveType read-only property of the NetworkInformation interface returns the effective type of the connection meaning one of slow-2g, 2g, 3g, or 4g.

via developer.mozilla.org

At time of writing, the effectiveType is capped at 4g, even when users are on 5g and are likely having faster internet.

bandwidth (in Kbps)

returns the effective bandwidth estimate in megabits per second, rounded to the nearest multiple of 25 kilobits per seconds

via developer.mozilla.org

The bandwidth is capped at 10Mbps.