What Is INP (Interaction to Next Paint)?

Purpose

Define Interaction to Next Paint (INP), explain why it matters for dealer sites, and describe what affects it.

What INP measures

INP measures how quickly a page responds visually to user interactions such as taps, clicks, and key presses. It reflects real responsiveness.

Google reference:

• INP guidance https://web.dev/inp/

Why INP matters on dealer sites

Dealership websites depend on fast interactions:

• Opening menus
• Filtering and sorting inventory
• Switching photos on VDPs
• Submitting lead forms

If interactions feel delayed, shoppers are less likely to engage.

Common causes of poor INP

• Long JavaScript tasks on the main thread
• Large bundles from third party tools
• Heavy page templates with expensive rendering work

How Speed Layer relates to INP

Speed Layer can improve early responsiveness by:

• Deferring selected non critical third party scripts
• Releasing deferred work after the page is stable

Speed Layer does not rewrite platform code, so some interaction delays can still be caused by the site’s own JavaScript.

Related pages

• How Speed Layer Improves Interactivity
• Why Third-Party Scripts Slow Down Dealer Sites
• Ensuring Critical Tools Still Load Properly