At the top of the page is a simple "Score" counter and "Increment" button. A classic demo of reactivity and responsiveness!
Below are 4 metrics:
- INP: the current INP score, which is ~worst Interaction
- Interaction: the score of the most recent Interaction
- FPS: the main thread frames-per-second of the page
- Timer: a running timer animation to help visualize jank.
The FPS and Timer are not at all necessary for measuring Interactions. They are added just to make visualizing responsiveness a little easier.
Try to interact with the Increment button and watch the score increase.
INP measures how long it takes—from the moment the user interacts, until the page actually shows the rendered update to the user.