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diagnostic · one of 36 free, no counter

Interactions

Why does this page feel laggy when I click?

A laggy page is a measurement, not a mood: the browser times every interaction and every animation frame that ran long, and this reads both. Each interaction keeps its worst event split into input delay, processing and presentation - the same arithmetic INP uses, applied to one press at a time - and beside it the long frames name the script that was blocking, host and path only.

Reach it Press + K on any tab and type interactions. Ctrl + K on Windows and Linux

Which press was slow, and which script made it slow
reads event timing and long animation frames
listens between record and stop, never before
history the browser buffers both from page load, so it is included
writes nothing
sends nothing
floor interactions over 16 ms earn a row
plan free
section#about

What this actually is

A button that visibly hesitates, a field-data INP number somebody has to explain, or a review where “feels sluggish” needs to become a script name before anyone can fix it. Press record, use the page the way the complaint describes it, and read which press paid and where the milliseconds went.

section#asked

Asked about this diagnostic

Why is there a record button instead of a reading on arrival?

Because the subject is what happens while the page is used, and using it is your half. The observers bind when you press record and disconnect when you stop, leave the tool or close the panel - nothing watches a page unasked.

How does it show interactions from before I pressed record?

The browser buffers these entries from page load, and connecting an observer hands the buffer over. That history is why the reading can be honest - an INP measured only from now would miss the slow press that made you open the tool.

What does the blocking number mean?

Long animation frames count the time a frame ran past 50 ms, and the total is what any interaction arriving during those frames had to queue behind. Each frame names its longest script by host and path, which is usually the answer to which bundle did it.

What counts as slow?

The same bands the field metric uses: under 200 ms reads as fine, over 500 ms as poor, and the worst interaction seen is marked as the INP candidate. One machine and one session, so it is the right reading for finding the cause and the wrong one for quoting a number.

how to use interactions

  1. Open Interactions and press record.
  2. Use the page: press the button that hesitates, type in the field that lags.
  3. Stop, then read the worst event split into input delay, processing and presentation.
  4. Take the long animation frame beside it to the script that owns it.