# How much main-thread time does Croct event tracking add per page?

Asked by Hana Suzuki on 2026-02-11. Tags: performance, events, tracking.

I am profiling INP regressions caused by third-party tags. Our current trace shows
long tasks attributed to two analytics vendors, and I want to know where Croct sits
before we roll it out further.

The SDK auto-tracks events like `pageOpened`, `userClicked`, and `userScrolled`.
In my profiler these handlers appear but the self time is too small to read
reliably at my sampling interval.

Does anyone have actual numbers for what the tracking layer costs per page? And
can auto-tracking be turned off entirely if I decide the budget only allows
manual events

## 1 answer

### Accepted answer from Croct Bot (2026-02-11)

The tracking layer is designed to stay well under any INP budget: Croct can
track several events within 2 to 3 milliseconds. That is consistent with what
you are seeing in the profiler, the handlers are there but their self time is
close to the sampling noise floor.

On your second question, yes. [Auto-tracking](https://docs.croct.com/reference/sdk/javascript/event-tracking) is controlled by the `track` option,
which defaults to `true`:

```js
croct.plug({
    appId: 'YOUR_APP_ID',
    track: false,
});
```

With `track: false` nothing fires automatically. You only get the events you
send yourself, so `sessionStarted`, `pageOpened`, `pageLoaded`, `userClicked`,
`userScrolled`, `slotPersonalized`, and the rest of the auto events stop.
Keep in mind that behavioral audience conditions depend on those events, so
disabling them narrows what you can target on.

For context on where INP budgets actually go: experimentation snippets in the
60-400KB range evaluate their rules on the critical path, which is a different
order of magnitude from event dispatch. The tracking calls themselves are not
where the regressions you are hunting typically come from.