Hi Vibhuti - I haven't been involved in the origin trials program for quite some time now, but I don't think the criteria has changed - usage is based on feature use, not on the presence or absence of the token in headers. It should be fine, for most trials, to ship the header on every page view, as long as you're not triggering the feature on every page load. We count the number of page loads where the feature is used at least once.
That said, the 1% limit applies across *all* page loads measured by Chrome; generally you would have to be an extremely large popular site to trigger that by yourself. A very large number of smaller sites could potentially cause the trial to reach this limit as well, though that is less likely for an origin trial, given that each site has to sign up for their own token. A rough but mostly-correct proxy for this calculation is the feature popularity metrics we publish at https://chromestatus.com/metrics/feature/popularity - if that number were to climb above 1% for a feature while it was still in an origin trial, that would likely trigger the usage limits. This is mostly documented in https://github.com/GoogleChrome/OriginTrials/blob/gh-pages/developer-guide.md#19-are-there-any-usage-limits-on-experimental-features Hope this helps, Ian On Tue, Oct 20, 2026 at 11:57 AM Vibhuti Mahajan <[email protected]> wrote: > Hi Blink Dev Community, > > We're planning to enable an Origin Trial for our web application and would > appreciate clarification on how the usage restrictions are enforced. > > We have two questions: > > 1. > > *What counts toward the usage limit?* Is usage measured based on pages > receiving a valid Origin-Trial response header, or only when the > experimental API is actually invoked? Specifically, can we send the token > to all users but restrict actual feature usage to a small subset, or should > we limit token distribution itself? > 2. > > *How is the usage percentage calculated?* Our trial disclosure > mentions a 1% usage limit. Is this calculated against our application's > traffic, or against total Chrome page loads globally? > > Any clarification or pointers to relevant documentation would be greatly > appreciated. > > Thanks! > > -- > You received this message because you are subscribed to the Google Groups > "blink-dev" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion visit > https://groups.google.com/a/chromium.org/d/msgid/blink-dev/a886dbf9-b11b-4290-a518-30d1bdbe17b4n%40chromium.org > <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/a886dbf9-b11b-4290-a518-30d1bdbe17b4n%40chromium.org?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "blink-dev" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAK_TSXKBg5xd8RcUW_qdXZyUsVX8-LA5C70ehOby8eSdVaqs2Q%40mail.gmail.com.
