What we keep, and for how long
A plain-language tour of our retention periods, and why access logs are the shortest.
Blog
Blog
Engineering notes on web performance, privacy and ad measurement.
Why our script is 1.4 KB
A telemetry script should never be the reason a page is slow. The budget, and what we left out to keep it.
Viewability that matches what users actually saw
An ad slot that is 'in the DOM' is not a viewable impression. How we count the ones that are.
Sampling beacons without skewing percentiles
Dropping beacons at random is easy. Keeping p95 honest while you do it is the hard part.
Measuring INP without cookies
Interaction to Next Paint is a per-page-view number. Here is how we report it without ever recognising a returning visitor.