Google search algorithms in 2026 place extreme weight on real user interaction responsiveness. With Interaction to Next Paint (INP) having fully replaced First Input Delay (FID), websites must optimize their main JavaScript thread to respond within 200 milliseconds.
1. What is INP and Why Does It Impact Rankings?
While FID only measured the first click on a page, INP measures every user interaction throughout the entire browsing session (taps, key presses, dropdown selections). A single long task blocking the main thread can ruin your URL group score in Google Search Console.
