Do the tracking and evaluate calls hurt INP on interaction?
watching INP on a few interaction-heavy pages. I want to isolate whether the client-side evaluate and event-tracking calls are adding main-thread work on clicks.
My concern is a click firing an event or an evaluate, and that work landing on the main thread right when the handler runs, dragging INP up. How heavy are those calls in practice?
2 answers
Tracking is lightweight. Several events go out in about 2 to 3 milliseconds, and events are sent without blocking the main thread on the interaction, so a click that fires an event is not sitting there waiting on a network round trip inside the handler. Evaluation is bounded too, CQL evaluation targets under 40 milliseconds.
So in practice neither is the thing dragging your INP. There is a closer look at the tracking side in event tracking main-thread cost.
If you want to remove the question entirely on a given page, resolve that content on the server. Server-side resolution means there is no client-side evaluate or content work happening on that page at all, so there is nothing to charge against INP for the personalization itself. You keep client calls only where you actually need them for interaction.
For budgeting how much an evaluate costs per pageview when you do keep it client-side, see the evaluate call per-pageview budget.