We measure our own
impact on your page
Every ad vendor says their tag is fast. Keystone measures its own share of your Core Web Vitals on real traffic, and only counts what is provably ours.
Speed is revenue. You deserve the real numbers.
Core Web Vitals affect search visibility and how long readers stay. When a page gets slower, you need to know whether the cause is your content, another vendor, or us.
Light from the start
The tag is lightweight and loads only the formats that apply to each visit.
Measured on real pageviews
Not lab tests. Keystone measures LCP, CLS and INP on your real visitors.
Ours vs. the page's
Each metric is split into what Babel caused and what the rest of the page caused.
Who caused it?
IllustrativeIllustrative example of how the split is reported. Your real figures come from your own traffic.
How we attribute each metric
The rules are deliberately strict: when in doubt, it isn't ours, and it isn't hidden either.
Largest Contentful Paint
Counted as ours only when the largest element on screen is one of our formats.
Cumulative Layout Shift
A layout shift counts as ours only when our Ad Wall gate or a player we placed caused it.
Interaction to Next Paint
INP and main-thread time are attributed by exact script URL, including the third-party scripts we bring in, such as Prebid, bidders and player embeds.
Numbers you can defend in a meeting
We would rather under-claim than over-claim.
Only what's entirely ours
Headline figures include only time that is entirely ours. Shared or uncertain time is listed separately and never added in.
The waits around us, too
We also measure how long the page waits for consent from your CMP, and for the country lookup, so nothing is hidden.
Honest about coverage
LCP is measured in all browsers. INP and main-thread attribution use Chrome's Long Animation Frames API, so they're measured on real Chrome traffic.
Want these numbers
for your site?
Talk to us and we'll walk you through how Keystone affects your pages.